___ ___          .__     _____   .____     .__   _____
   /   |   \ _____   |  |  _/ ____\  |    |    |__|_/ ____\  ____
  /    ~    \\__  \  |  |  \   __\   |    |    |  |\   __\ _/ __ \
  \    Y    / / __ \_|  |__ |  |     |    |___ |  | |  |   \  ___/
   \___|_  / (____  /|____/ |__|     |_______ \|__| |__|    \___  }
         \/       \/                         \/                 \/
  ________                                   .__
  \_____  \  ______  ______    ____    ______|__|  ____     ____
   /   |   \ \____ \ \____ \  /  _ \  /  ___/|  | /    \   / ___\
  /    |    \|  |_} }|  |_} }(  {_} ) \___ \ |  ||   |  \ / /_/  }
  \_______  /|   __/ |   __/  \____/ /____  }|__||___|  / \___  /
          \/ |__|    |__|                 \/          \/ /_____/
              \_   _____/  ____  _______   ____    ____
               |    __)   /  _ \ \_  __ \_/ ___\ _/ __ \
               |     \   (  {_} ) |  | \/\  \___ \  ___/
               \___  /    \____/  |__|    \___  } \___  }
                   \/                         \/      \/

                     Guide\Walkthrough Version 1.08

                   written by Stijn Bolle (26-03-2000)
                   e-mail: [email protected]


  1 Updates
  2 Introduction
  3 Walkthrough
    3.1 Welcome to Black Mesa
    3.2 We're pulling out
    3.3 Missing in Action
    3.4 Friendly Fire
    3.5 We're no alone
    3.6 Crush Depth
    3.7 Vicarious Reality
    3.8 Pit Worm's nest
    3.9 Foxtrot Uniform
    3.10 The Package
    3.11 Worlds collide
    3.12 The end
  4 New monsters
  5 Cheats & Tricks
    5.1 Easter eggs
    5.2 Cheats
    5.3 Xen Locations
  6 Links, Greets & Questions
  7 Author
  8 Legal Notice

I Updates

  *** Version 1.08 (26-03-2000)

   - Some minor changes and corrected glitches.

  *** Version 1.07 (9-03-2000)

   - An easter egg has been updated

 *** Version 1.06 (8-03-2000)

   - Some changes have been made to the walkthrough

   - A neat trick has been added by Crash Easton

   - This guide has been chosen as the cheatmaster's choice at the avault
     games site (www.avault.com/cheats). [March 5th 2000]

 *** Version 1.05 (7-03-2000)

    - I added four more easter eggs to the easter egg section (I'm pretty
      sure no-one else found them, so they're worth checking out). I
      almost can start write a Half Life: opposing force easter egg guide,
      which means they have a good sense of humour at Gearbox.

 *** Version 1.04 (6-03-2000)

    - A smaller update this time, but I'll update the guide as soon as I
      have some new information now, because I lose it otherwise :)

    - There's a new easter egg available.

    - A new Xen location has been added

 *** Version 1.03 (5-03-2000)

    - A dutch version of my walkthrough is available for download, you can
      download it from www.gamefaqs.com

    - My contact information has changed, so if you want to mail me, make
      sure you use my new mail address.

    - A LOT of new easter eggs have been added. On the last update, I
      thought I had found them all ... but I was very strong, there are a
      lot of things that still were hidden, check out the easter eggs
      section (5.1)

    - The cheatcodes (5.2) have been updated

    - Various changes have been made

 *** Version 1.02 (4-02-2000)

    - A new section has been added: Xen Locations (5.3), on different places
      in the game, it's possible to warp to Xen by using your displacer. I
      think I've found all places, but you can mail me new ones if you found

    - I added some more easter eggs to the easter egg section (5.2)

    - The cheat codes (5.1) have been updated

 *** Version 1.01 (31-12-99)

    - The cheats have been updated
    - Another easter egg has been added
    - Some parts of the walkthrough have been modified

 *** Version 1.0 (27-12-99)

   - This is the first version of this file. Everything has been added. I
     don't expect to add much more, but if you have some interesting
     information to add, don't hesitate to mail me.

II Introduction
  Half-Life: Opposing Force is an official expansion pack for Half-Life
  being developed by Gearbox Software and published by Sierra Studios. In
  Opposing Force, you play a soldier, Adrian Shephard that is sent to the
  Black Mesa Research Facility to clean up the mess created by Gordon
  Freeman. Not only will you see Gordon Freeman sometimes, you'll also often
  visit the same places he visited, but at another time.

  The expansion pack was released in November, 1999 in the US and December,
  1999 in Europe. Since I live in Europe and I had exams, it took a while
  before this guide was written, but I finished the expansion pack in one
  day and wrote the core of this guide the same day.

  Gearbox did an excellent job on the expansion pack. Although they were
  under 'very strong surveillance' from Valve and although they hadn't
  developed anything yet (their game Prax Wars was canned), they created
  the same intense atmosphere from Half Life and had some nifty ideas
  themselves in the game. What to think about the puzzle where you have
  to activate the "Gearbox" and "Valve" ... and the easter egg with the
  speech of the boss. There's more, but I'll tell you that below.

  The game's 70% long of the original Half Life and features new weapons,
  new enemies, new levels, new squad team mates, ...

  Now who is this Adrian Shephard you're playing with and what does he
  have to do with the story? Remember the marines who gave you so much
  trouble in Half-Life? Now you are one of them and life is not so easy as
  part of the Opposing Force.

  When Freeman gets out, the powers-that-be who caused you so much hassle
  in the first instalment resort to Plan B, sending in the Black Ops. As
  one of your nation's finest fighting specimens, you dive into the world of
  Black Mesa. As a soldier sent in to eliminate Gordon Freeman, you are
  separated from your base unit and discover a new alien race amidst the
  chaos. It's quickly revealed that these highly advanced alien life forms,
  known only as Race X, descended upon Earth to pillage the planet from the
  Black Mesa facility when Gordon Freeman transported to the border world of

  Just as Gordon discovered when he encountered hostile life forms in
  Half-Life, if you can't live with them, you'd best live without them.
  Thus, it's your characters duty as a Black Op to sort out this mess, even
  though he's quite on his own.

  I played the game on the medium difficulty and I don't know whether
  changing the difficulty brings up more enemies, I suspect you only
  sustain more damage. Anyway, I just walked around and noted everything
  down I saw. Go on and read the walkthrough now :)

III Walkthrough

  3.1 Welcome to Black Mesa

  After the truly magnificent intro (look to the background for some scenes
  from the original Half Life), you awake inside a scientist's room. Talk to
  the scientist and he'll tell you what's happened. He mentions a radio
  somewhere outside, it's your first mission objective. Go through the door
  and turn right. Turn left and go through the double doors. Look through
  the window, you see some scientists. Turn left and walk to the back. Talk
  to the scientists there (there's one poking a crab). Walk to the back and
  get your power vest from the table on the right. Now return and go left,
  left, right. Look through the window and you see a scientist and a zombie
  grunt in the same room. The zombie grunt wakes up and kills the scientist.
  Yikes. Don't near the window, but go to the left. Crawl to the opening in
  the left of the door and go down the stairs. Talk to the security guard
  and walk to the door. He'll open it for you. Before proceeding to the next
  area, you may use this neat trick Crash Easton sent me to get the desert
  eagle . When Otis opens the door for you, push the chair that`s in the
  room so that it blocks the door. Go grab the wrench and come back. The
  chair will keep the door open and you can crouch jump on it to get back
  to Otis. Introduce him to mister wrench (you may have completely destroy
  his body since he`ll hold to the gun). Having this gun will make the
  first few headcrab less of a pain in the ... or even better go back to
  the scientists near the start point and give them their daily lead
  requirement since they`re all going to die anyway thank to G-man. Then,
  you can proceed to the next area.

  There's an electrical wire in the middle of the gangway. Don't touch it or
  you'll get electrical damage. Get the wrench next to the toolbox and walk
  past the electrical wire. You'll enter a room with two beams. You can
  crawl under the green beam. You need to go up the stairs, but the purple
  beam is blocking your path. There's no way to get past it, so read the
  sign on the wall, it says "optical mirrors are very fragile". Use your
  wrench to destroy the optical mirror that reflects the beam over the
  stairs. Go up the stairs then and turn right. Walk forward and the ceiling
  will cave in. Kill the two headcrabs and turn left. You'll see a green
  substance on the floor. Near the substance and retreat at once, a headcrab
  from the left will attack you. Jump across the green pool and jump back
  then. Another head crab will attack you, but it will kill itself if it
  touches the pool when following you. Jump across the pool then and turn

  Look through the door to the right. You see that strange man in the suit
  there, together with a security guard. You can hit the glass to draw their
  attention, but they won't open the door for you. Smash the grates and you
  discover a medikit and an energy cell. Go up the stairs and through the
  door. Smash the crates to find another medikit. Go through the door then
  and you're outside. Go to the right and jump across the gap. It's not
  possible to reach the stone slab, you'll land on the grass below the slab.
  Jump further some more time and jump to the left then, on the small stone
  slab. From there, you can jump to the building to the left. You saw this
  place during the intro too. Walk over the body of the alien slave to get a
  knife. Jump over the gap then and enter the building. Watch out, there's
  a headcrab inside. You can lure him to jump in the gap, but the falling
  damage won't kill it. At least, it can't hurt you from there. Go to the
  back of the building and crouch to enter the small entrance to the right.
  Follow the tunnel.

  Walk down the pipes and you enter another place from the intro. You need
  to get to the area past fence, but some beams are blocking your path.
  Don't touch the fence, there's some serious voltage. You need to find a
  way to shut down the power. Walk through the big doors on the right. Kill
  the headcrab. Watch for the gap in the wall on the right, some more
  headcrabs will appear. Kill them and exit through the big doors. Walk
  towards the iron cage and a security guard will near you. Of course, he's
  foolish enough to touch the fence and kill himself. Destroy the crates for
  some more medikits. Go through the small entrance between the big door and
  the cage then. You may need to use your nightvision in here. You'll enter
  a small room with a fan. There are some electric beams, so make sure not
  to touch them. Look to the right and wait until the beam disappears. Move
  forward and wait for the second beam to disappear. Go further and enter
  the small tunnel. Exit and you're inside the cage. There are more beams
  here. Carefully move to the left and then forward. Make sure not to touch
  the fence. Grab the gun (the .357 Desert Eagle, but I'll call it the
  magnum from now on) and crouch to the right below the beam. Go right then
  and you see the "Generator Control" box. Press the "use" key to shut down
  the elevator. Leave the cage through the door then and go through the
  double doors to the right. As soon as you enter, equip your magnum and
  walk backwards. An alien slave will appear, one shot will kill him. Walk
  further then and kill another alien slave.

  You're back at the helicopter wreckage then and you can go past it now.
  Walk to the radio in front of you and listen to the orders of your
  commander. Destroy the crates next to the radio for some ammo. The crates
  to the right hold a medikit. Enter the hole on the left then and follow
  the ladder down. Go down the next ladder. Turn right. Watch out, there are
  some barnacles on the ceiling here. Avoid them and go to the left. Go
  through the door and you're back outside.

  Go through the door in front of you and follow the hallway. Kill the alien
  slave and get the shotgun next to the marine. Look down and take out the
  alien slave below you before it spots you. You'll have to stand on the
  edge to take him out, you cannot shoot it through the landing you're
  standing on. Follow the ladder down then and take out another alien slave
  a level below you. Crouch to avoid the steam and don't touch the barnacle.
  Go down the ladder and go through the door. Go through the right. Jump
  down and go stand behind the unbreakable dark green box on the right. A
  platform in front of you will come down. As soon as it's down, strafe to
  the left, and take out the alien slaves to the platform. Inside the
  crates, there's a medikit. Go to the left then.

  You reach a tricky part here, so be quick and watch out. Jump over the
  small gap and run to the ladder to the right. An alarm goes off and there
  will be electrical beams everywhere that destroy the platforms. Go up the
  ladder quickly and ignore the electrical beams (you will sustain some
  damage). Go stand in front of the door to the right then and watch how the
  beams take out everything. The level of the green toxic waste will start
  to raise. Look to the window to the left. The man in the suit will appear
  and will open the door for you. Enter the gangway and go up the elevator

  Do a crouched jump to get the ammo from the left. Then jump over the toxic
  waste and destroy the crates (not the flammable ones) for some extra items
  There are a lot of nasty headcrabs between the crates here, make sure they
  don't surprise you. You can lure them into the toxic waste if you've got
  some timing. Go to the right then and follow the stairs to the control
  room. Hold the conveyor control button until the conveyor moves almost
  completely to the left. Go to the conveyor then and use the crates to jump
  on top of it. Get the energy pack from the left and press the button there
  to open the cargo door. Jump over the toxic waste into the next room.

  Walk past the bars and to the left then. Look to your right, you see a
  broken pipe. Jump inside and the flow will take you into a big pool. Avoid
  he barnacles and follow the water until you see a ladder. Go up the ladder
  and over the bridge. Get he ammo and the grenade from the right. Go to the
  left. In the next room, you can't take the ladders down. Look to the sign,
  it reads "no access during robotic loader procedure". Look to the robot to
  the left. He's stuck because some crates are blocking his path. Shoot the
  crates and the robot will leave the room. Once he's out, you'll be able to
  go down the ladder. Go down the ladder in the back and use the crates to
  jump to the other side. Press the button at the toxic waste overflow
  system and wait until the area is drained. Walk to the big door in the
  back then and push the button. Go through the door and push the button in
  the back to ride the elevator up.

  There are some sound dogs up here. Take them out before they can use their
  sound wave attack. Go up the slope and walk to the bed with the plank on
  it to the left. Push it towards the tram. When it's in front of the tram,
  use the crouch jump to get on the plank and jump inside.

  3.2 We're pulling out

  This level doesn't start too easy. The tram will bring you up. First kill
  the alien slave attacking the scientist. Next, as the tram brings you a
  little higher, take out the two alien slaves (there's one on each side).
  As you continue, you will see an alien slave running in the shaft below
  you. Kill it. The final alien slave is inside a tram that cross your path.
  You can take him out or dodge his beam. The tram will stop and you can
  step out. Take the ammo to the left. As soon as you take it, two alien
  slaves will appear, one in front of the train and one on top of it. Take
  out the one in front first, then the next one. Go to the left and you'll
  meet a security guard. As him to follow you. Let him take out all enemies
  you meet in the next area. Go up the stairs to the left then and look
  through the window. You can't go though the door. The security guard and
  the scientist will be killed. A beam will break the window, so make sure
  you're not standing in front of it. Jump through the window and walk
  towards the door to open it for the security guard. Walk straight forward.

  Walk to the door to the right and the security guard will open it for you.
  Inside, you find some ammo. Break the glass window on the left and jump
  inside. Talk to the professor and he will heal you. Walk straight ahead to
  the elevator. Look behind you, there's a broken grate in the wall and some
  headcrabs may leap out. Once going up, you hear some gunfire. Equip a gun
  and take out the alien slaves. There are three of them, but usually, the
  marine is able to take out one. Get the machinegun near the corpse of the
  marine and search all the crates for some ammo. Don't forget to load your
  armour on the HEV station.

  There's a security door here, but the security guard refuses to go with
  you, so you have to find another way. Jump on the crates to the right and
  then on the HEV station. Break the grate and follow the tunnel until you
  reach a ladder. Go up the ladder and enter the next room. Look through the
  window, there are some helicopters there. Heal yourself on the medic
  station and go through the door. Talk to your chief, you have to get to
  the hangar. Get the grenade and the satchel charge from the desk. Destroy
  the crates for some more ammo. Go to the marine at the door, he's
  threatening a scientist. Get past the scientist and use the crates to get
  the power cells. Then, destroy the small grate and follow the tunnel down.
  Destroy the crates and go through the door, the fire door will shut behind

  Walk to the door to the left, the man in the suit has closed it. Wait
  until the helicopter takes off and turn around then. Take out the alien
  slaves that appear and go through the hole in the wall on the left then.
  Go to the right.

  3.3 Missing in Action

  Go to the left and move forward when the steam disappears. You have to
  crouch now, to move under the pipes. Near the back wall, you see a
  headcrab. Take it out with your pistol. Make sure not to touch the liquid
  on the floor there. Go to the right and two alien slaves appear. Take them
  out. Search the room for some ammo and two power cells. Next, go to the
  set of pipes to the right of the position of the dead headcrab. Climb the
  pipes and smash the grate to the right. Enter the small tunnel. There's a
  grate in the floor. Ignore the first one and smash the second one a little
  further. Jump down and get the medikit from the shelves. Now, go through
  the door and you're back in the first room. Climb the pipes again and
  follow the tunnel. Now smash the first grate and drop down

  Below you, there's a pool with an electrical wire. Make sure not to fall
  down or you'll sustain damage. There's an energy cell on a platform
  floating in the pool, but usually, you're at 100% armour at this point, so
  you won't need it. Avoid the tiles in the floor with some
  markings on it end. If you stand on one of those, they will
  drop down. At the end, go right and you reach some fans.

  Walk over the small bar and turn right. Jump to the bar at the other fan
  and go right then. Wait until the first team disappears, then quickly walk
  past the second one. If you really don't want to get any damage at all,
  you can also jump on the railing to the left. And then jump to the
  platform past the second steam as soon as the first one disappears. Jump
  to the platform with the door then. Kill the zombie scientists inside
  and search the crates for some ammo. Return and go to the right then.
  There are some fans in front of you.

  Walk in the exact middle of the path between the two fans and they won't
  be able to touch you. Go down the ladder and go stand in the exact middle
  of the path between the next two fans. Don't go to the other side of the
  room, go stand in the middle, halfway the path and look to the right. The
  fan only has one blade and below the fan, there's a broken grate. Crouch
  and as soon as the blade passes you, moved forward (crouched) and enter
  the tunnel behind the grate. Jump down and destroy the grates at the end,
  you have to get past some fires now. Wait until the trail of the fire is
  gone and jump. Don't touch the fire, even when you see only a little left.
  For the next fire, it's easier to cross when you stand on the first crate.
  Your timing has to be perfect here, you cannot wait until the fire has
  gone completely. As soon as you see there are only a few sparkles left,
  jump. If you time it right, you can get to the other side without getting
  hurt, just jump a little earlier than your instinct tells you to do :)

  Jump to the other side and take out the zombie grunt and the headcrab
  there. Search the crates to the right for an energy cell and a medikit.
  Break the grate in the left wall then and follow the tunnel. Break the
  grate below you and jump down. More fires. Move forward as soon as the
  fire disappears. The next fire is a little more difficult: you have to
  follow the fire to the left. As soon as it's gone, run inside the tunnel
  to the left and jump to the ledge on the right then. From there, take out
  the zombie grunts on the other side. Strafe to avoid their balls. Jump to
  the other side then and kill the zombie scientist and another grunt

  Search the marines in the back for some more ammo. Go to the left then.
  There's a fire testing procedure here. There are signs that read "do not
  obstruct the testing process). Naah, do it anyway :) There's an explosive
  crate somewhere around. Push it inside the fire testing tunnel and press
  the "test fire" button then. The explosion will create a hole in the floor
  to the left. Jump inside. Take out the zombie grunt and the headcrabs in
  the tunnel. At the end, look to the pipe to the right. Kill the headcrab
  and get inside then.

  Go to the right and break the grate, you're back outside now. Go straight
  forward and jump down. Turn around, there's another grate there. Get
  inside the tunnel and you find some ammo. Jump down then and walk to the
  truck. Talk to the marine and enter the building. Search the back of the
  truck for some ammo. Go to the left then, you'll hear some monsters
  running on the platform above you. Search the crates for a medikit. You
  see two doors with a button to the left. Ignore it and go to the right
  around the corner. Kill the two pit drones (one shot of your shotgun does
  the trick) and search the area for a medikit and two power cells. Return
  to the two doors then and press the button. The door to the right will
  open. Kill the four pit drones inside. Search the back of the truck to
  the left for a trip mine. Go up the stairs then, to the left, there's a
  power cell. Go to the right and search the crates, you find a satchel
  charge and a RPG.

  Go straight ahead then and kill the pit drones. You can talk to the
  scientist, but none of them seems to like you. Look through the door on
  the left. Jump to the ledge on the left and go down the ladder then. Take
  the next ladder down and walk to the elevator box. Climb up the grate
  inside and jump through the hole in the wall into the next room. Go to the
  left, you see a sign "caution, wet floor". Make sure not to touch the
  water or you'll get some electrical damage. Jump on the sign and then
  on the crate straight ahead. Jump to the left the and get over the crates.
  Go to the left and push the door to enter an area called "unit 2 power".
  Turn off the power with the "use" key and destroy the crates for some ammo
  Leave and go straight ahead past the crates. Return to the elevator shaft
  and go up the two ladders. Go to the right then and jump towards the
  electrical wire. Climb it up and jump on the elevator box in the air then.
  Enter the box for some power cells and enter the room then.

  Go to the left and follow the gangway. You'll be in front of a locked door
  but there's a grate to the left. Break the grate and use the tiny box a
  little further to get inside the tunnel. When you continue, the tunnel
  will collapse. Leave the tunnel and turn around. Go to the area behind the
  tunnel and kill the bull squid there. Next to the marine's corpse, there's
  some ammo. Return and go to the right then to leave the water.

  We'll have to do some puzzling here. First, go to the door in the back and
  push the blue crate into the area you came from. Push it to the pile of
  garbage to the right (with the garbage bin with the word "push" on it).
  Use the box to get over the garbage. Look to the room to the right then.
  Break the window and throw a grenade inside. Seek cover and the wall will
  explode. Get inside the room and go through the wall to the right. Now,
  you can push the blue box, through the hole in the wall past the pile of
  garbage. There's another grate there, break it and use the blue box to
  get inside. Just around the corner, there's a headcrab. Kill it. Break
  the grate and enter the next room. Walk straight ahead and a headcrab will
  leap down from a crack in the ceiling. Kill it. Look to the left, there's
  a hole in the floor with scientist. Get the power cells and walk to the
  back of the room then. Turn off the power and climb the wire up then. Jump
  down on the next level.

  Go to the right, there are some dead people there. Use the radio. Two
  marines are nearby and they're going to blow the door. Wait until the door
  in the back explodes. Order them to come with you and go to the door to
  the left (the elevator). One of the marines will burn the door open and
  you can get through. Wait until you all stand in the elevator and press
  the button then.

  3.4 Friendly Fire

  This level starts with some heavy action. As soon as the elevator door
  opens, your squad members rush out and attack the alien slaves in the next
  room. It's possible a squad member gets killed and that's no problem, as
  long as the one with the burner survives. While you take out all the alien
  resistance in the room, he will burn open the exit in the back. When the
  area is clear, follow him. Go to the building in the back for some weapons
  Leave the marine there. Return and go up the stairs. Go through the door
  and enter the office on the right. Kill the alien slaves inside and get
  the ammo and the health pack. Leave the office and go through the door to
  the right.

  Slowly walk forward. As soon as you hear the alien slaves teleport.
  Retreat and take them out. Enter the room again and walk forward. Another
  alien slave will appear together with an alien grunt. Kill the both of
  them and go through the door to the right, this is the meeting room. Kill
  the alien slaves inside. When you walk forward, the wall on the left will
  explode and another alien slave appears. Kill him.

  Go through the hole in the wall and kill the rest of the alien slaves. Go
  through the door to the right then. There's a crack in the wall in the
  back. Climb inside and use the pipes to go up a level. Use the blocks of
  stone to get another level up. There's a power cell here, next to a
  scientist. Make sure not to touch the barnacle next to it. Jump to the
  other side and climb the ladder up. Run over the bridge and leap over the
  gap. Open the door in the back. Turn left. There's a big pool in front of
  you with toxic waste. On the other side, there's an annoying alien grunt.
  When he stands in front of the explosive crates, shoot them to take him
  out. This area seems uncrossable, but it's possible. You need to swing
  with the purple wires to the other side. Make sure not to touch the
  electrical wire while crossing. If you want to be surenot to get hurt,
  simply shoot one of the power transfer nodes and the whole system will
  die, leaving the wires safe to swing on. Swing to the other side and
  search the crates on the right then for some ammo.

  Ride the small elevator up on the right and you find more ammo. Watch out,
  there may be a sound dog around here. Use the radio to listen to your
  chief. You can't hear anything at all, except they're under attack. Go up
  the slope to the right and kill the sounds dogs. Use the construction to
  get out of the hole and talk to the marine, he's a medic. To make him
  heal you, simply keep the "Use" key pressed when standing in front of him
  (ignore his speech). To the left of the marine, there's a broken pipe. Get
  inside and go to the right. Break the grate and you see a strange missile.
  Go to the left then and watch out here, there are some heavily armed
  black-ops agents. This is one of the most exciting parts of the game.

  Break the grate and retreat at once, it's not possible to take them out
  by surprise. When they stop shooting, move back into the tunnel and wait
  until they appear. Take them both out, then leave the tunnel and go right.
  Go around the rocket and kill another black ops agent from behind by
  surprise. Search the crates and go to the left then. Stay behind the truck
  and throw some grenades to the area to the left, there are two to three
  blacks ops agents there. When they try to run from the grenade in your
  direction take them out with your machine gun. When they're all dead,
  return to the medic to regain some health.

  Return inside the building then and open the door to the left with the
  button. There's a marine inside and he needs medical attention. Go to the
  the other side and take out the sentry gun, open the door and order the
  medic to follow you. Lead him to the marine and let him fix him up. Order
  the both of them to follow you. Lead them outside, to the secure access
  door the medic mentioned. The marine will burn the door ... and get killed
  at once by the sentry gun. Take out the sentry gun and enter. Walk
  straight forward and you meet some more marines. Order them to follow you,
  you'll need their help. In the next area, there are a lot of black ops
  agent and they're extremely deadly. Let your squad members handle the left
  side of the area while you take care of the right side. As soon as you've
  secured area, assist them and nobody of your squad should be dead.

  Go up the stairs then and pull the lever at the end, the secure door in
  the back will open. Return and go to the left, to the new area. On the
  left side, there will be an opening with some health and ammo. Walk
  forward and you'll meet more black ops agents. Keep you're squad close to
  you and move forward slowly, while securing every area. When everybody's
  dead, gather the ammo, health and armour and go up the stairs. Pull the
  lever and return to the rails. Go stand on the cart and drive back until
  you see a post. Go past the post and hit it, so it flips. Then, drive the
  cart forward again and it will turn to the right now.

  Keep driving until there's another blacks ops agent on your left. Take him
  out and jump through the window inside the room to the left then. Gather
  all the weapons inside and use the small box then to get on top of the
  pipe. Follow it up and break the little grate on the right then. Follow it
  and exit.

  3.5 We're not alone

  This is a very weird part. Go to the right and you see Freeman gets inside
  the machine that teleports him to Xen. Run inside the room and avoid the
  fireballs of the monsters. On the other side of the room, a bridge will
  collapse. Climb it and jump inside the teleport. You appear at Xen.

  Your aim here is to get inside the teleport high up in the air. To get
  there, use the various jump pads to get on higher levels. There's not
  much to explain here, but at a certain point, you'll find the displacer.
  If you use it on yourself, you will be teleported to the hazard course.
  There, you have to take out some alien slaves, then do a bit of the course
  and crash the window to step in the teleport and return to Xen. You don't
  have to do that, though. When you finally touch the teleport ball in the
  air, you return to earth.

  3.6 Crush Depth

  Enter the elevator on the left and ride it down. Go to the right, you see
  a scientist with a radiation suit inside an aquarium. Kill the pit drones
  and use the stations on the wall to fix yourself up. Next, press the
  button at the control panels to release the scientist, he can open all
  secured doors for you. Order him to follow you and go to the other side of
  this area, there's a secured door there that needs identification. Let the
  scientist open the door and kill the squid bull inside the next room.

  Go to the next door and let the scientist open it. Oops! You have to find
  another way to get past the door. Return and look to the right, there are
  three aquariums and the one in the middle is broken. Climb the ladder up
  and take out the pit drones. Use the grate to get on the platform where
  the pit drones were and go to the right. A hole in the wall will appear
  and more pit drones will attack you. There are also often pit drones that
  fire at you through a hole in the ceiling, so watch out. Go through the
  hole on the right and kill the pit drones left. At the end of the room,
  crouch to the small tunnel and break the grate at the end. Jump down.

  There's some ammo in the back. Next, enter the cabin and push the button.
  You will be teleported into the water. Immediately swim to the right and
  exit the water. You reach a small area with three zombie grunts and two
  head crabs. Take them out and go through the small grate at the end. Jump
  down and you fall into a pool. Swim to the ladder in front of you and go
  up. In the next room, there's a zombie grunt, a zombie scientist and a
  headcrab. They're easy to kill. Go down the ladder and kill the two zombie
  scientists. You can't use the medical station in the back, it's broken.
  Use the HEV station and go down the ladder then. Go to the back of the
  room and turn the wheel to release the big monster in the aquarium. Now
  return to the pool.

  Jump into the water and use the displacer on the big water monster to warp
  it to Xen. Swim into his aquarium then and turn the wheel to the left to
  drain the water. Walk forward through the door. Go to the left. Some blue
  electrical rays are blocking your path. Shoot the control box near the
  ceiling behind the rays to disable them. Go through the door then and
  some monsters will appear. Kill the two pit drones and use the displacer
  on the shock trooper. Grab the ammo from the right and go to the left
  then. Enter the airlock and press the button. Go through the next door
  then, grab the ammo and step inside the teleporter. You appear at Xen.
  Walk into the next teleporter and you're back at earth. Push the button
  and the door to the right will open. Jump inside the water and use the
  displacer when both monsters are close to each other. Swim up the small
  shaft then and smash the grate. Walk straight forward.

  3.7 Vicarious Reality

  Walk forward, up the pipe and shoot the headcrab behind you. There are
  more headcrabs in this room, so take them out. Go to the right and you
  enter an observation area. The door in front of you is locked, so there
  may be a problem. Behind you, some monsters appear. Take them out. Due to
  their teleportation, one of the windows is broken, jump through it into
  the observation area.

  A giant spider, the voltigore, appears. Now you kill it, flee or use the
  displacer on it. When it's gone, push the button in the small room in the
  back, push the button to bring an elevator down and ride it up. Go through
  the door and kill all aliens inside. Go to the right and press the right
  button, this opens a window where you can find some snarks. Go through the
  next door then. There's a medical station on your right. Go to the left
  and search the storage rooms for some energy cells and ammo. Watch out,
  if you open the door to the left storage room, a headcrab leaps towards
  you at once. Go to the elevator and break the upper right window. Jump
  through it with a crouched jump. Climb the grate to get on top of the
  elevator box. Climb the ladder up.

  Get on top of it and jump on the ledge. Then, look down and jump on the
  door a little lower. Walk straight forward then and turn left. Follow the
  tunnel through various doors until you can turn left. Ride the elevator
  down. Turn right, there's a medical station there. Go through the door and
  kill the pit drones inside. Break the window then and step outside. Follow
  the ledge to the right down. There are some plants in there with a sharp
  tail, they will take out the sounds dogs. Jump down then and step on the
  little green plants to get a spore for the sporelauncher (you don't have
  it yet). Go to the small door to the left and press the button to open it.
  Ride the elevator up and get the sporelauncher from the right.

  Walk around the corner and go past the door. Kill the zombie grunt and
  get another spore. Walk through the door then and go straight ahead,
  through the tunnel. A mysterious light appears in front of you. Go
  through the door. Enter the door on the right and take out all the sounds
  dogs in the room. In the next room, you can push a button to the right. A
  hologram of a scientist appears and you get to know they have been
  experimenting with the barnacles. Go through the next door and get the
  barnacle from the showcase, it's a barnacle gun. You cannot use it as a
  grappling hook on a stone wall, but it serves fine to tear off the head of
  organic creatures. You can experiment a bit with it in the next room. Get
  the power cell then and go through the door.

  Kill all the pit drones here and enter the pit. Get some spores and use
  your barnacle gun on one of the organic things on the wall to get to the
  other side. Go down the elevator and kill the headcrabs in the next room.
  Avoid the barnacles and go through the door on the other side. Ride the
  elevator up and go through the door. Kill the pit drone and the shock
  trooper. Go straight ahead then and ride the elevator up. Once up, kill
  the pit drones and the shock trooper. A little further, you find some ammo
  health and energy cells. Then, take the elevator back down and return
  where you met the first shock trooper. Go up the stairs and through the
  door. You see a danger sign. To the left, we have these annoying creatures
  from the original Half Life again.

  If you hurt it enough, it will retreat for a short while and that gives
  you the opportunity to pass. It's not always necessary to hurt it, though,
  sometimes you can pass and it misses you. When you passed it, jump down
  and collect all the items you can grab without getting hurt. Next, use
  the barnacle gun on one of the organic structures on top of the wall, next
  to the hole. Get inside the hole and enter the tunnel. Go to the right,
  follow the tunnel and exit. Get down and collect the ammo. Listen to the
  radio, they are in trouble with a big worm. Shut down the power to unit 1
  with the lever. Then, climb back up to the other side of the room and
  smash the grate. You can pass the fan now. Follow the tunnel.

  3.8 Pit Worm's nest

  Cross the pool and look to the upper right window in the back. The man in
  the suit is watching you again. Open the door in the back. Kill the bull
  squid in the next room. Push the lever to the right of the door and enter
  the next room. Climb the ladder in the back and gather all the ammo from
  the marines. Open the door and face the pit worm. It gets tough from here.
  Like the tentacles monster in the "Blast Pit" level of the original Half
  Life, gunfire doesn't hurt it, there's a special process to take it out.
  Go through the door and jump down to the ledge directly below. Run to the
  right. If the monster already has hurt you at the moment, you first have
  to shoot it in the eye to distract it for a short time. Inside, kill all
  the pit drones. The door in the back is broken, so return. Next to the
  boxes and the corpse of the security guard, you find a spore and a grate.
  Smash the grate and follow the tunnel. You end up on a room with a button
  to 'flush' the toxic waste. Unluckily, you can't do that yet. Go through
  the door on the left and you're on the lowest level near the worm. Run to
  the right and press the button to close the door. You enter the waste
  station 2. Kill the pit drone and go down the ladder. Go through the door
  on the right, you're now in a room with a lot of crates.

  Get past the crates to the other side of the room. Go through the door and
  jump past the barnacles over the green pool. Ride the elevator up. Kill
  some more pit drones and push the button. Two walls in the crates room
  will close in. Return to the room. Get all items. In the middle, there's
  a grate. Smash it and you'll drop down in some water. Smash the glass
  and kill the bull squid in the next room. At the end of the room, turn
  right, you read the word "outtake". Push the button to the right and the
  water level will start to raise. Run back fast and let the water take you
  up again. Return to the big worm then (up the ladder and pull the lever
  to open the door).

  Run back to the waste control room. The light "gearbox" lights up now,
  but "valve" still needs to be activated. Take the door on the other side
  now. Climb the ladder and take out the pit drones. Quickly run outside,
  pull the lever and the "vent" will be activated. Avoid the green beam of
  the pit monster. Go down the ladder again into the waste control room.
  You still need to activate the valve now. Return through the grate you
  used to enter the waste control room. The iron stairs above you are broken
  so use the two crates to get back on them. The pit monster is still
  looking for you from the lower level. look in front of you, a bit up, you
  see some green organic structures. Use your barnacle gun to get cross the
  distance at once. Turn the wheel and the valve will be activated. By the
  time you've done this, the pit monster will have noticed you, so you'll
  have to hurry. Return from where you came and go back, through the tunnel,
  into the waste control room. Now that the valve & gearbox have been
  activated (check the names, those companies created the game), you can
  push the flush toxic waste button. The monster will get killed (finally).
  Now, get back, all the way up, until you get to the bridge control. It
  isn't blocked anymore, so press the button and a bridge will be formed.
  Cross the bridge. Pull the lever next to the door and continue.

  3.9 Foxtrot Uniform

  Go through the door. Kill the bull squid at the end of the area. Walk to
  the end then and go to the right. Kill the bull squid and search the
  crates for some medikits and power cells. Use your barnacle gun on the
  organic structures to get on top of this room. Jump to the ladder then and
  climb it up. You see a black ops truck arrive. Take out the three agents
  that step out from the truck. Just around the corner, there's someone with
  a nasty sentry gun. Use your RPG to take him out at once.

  Go to the red crate then and enter it. Watch out, some black ops agents
  may be throwing grenades towards you. From that position, take out the
  black ops in the next area. There are two on the ground and one in a tower
  If you want to play it safe, you can use some snarks to distract the ones
  on the ground. In the meantime, finish them off. The one in the tower
  is harder to get. You can try to get out of his sight, but a shot from
  your RPG also does the trick. Destroy the crates and go to the back then,
  there's a small entrance to the right. Enter the room, there are some
  marines here. Grab all the ammo there and order your squad members to wait
  they can't do anything at the moment.

  First, go back outside and throw a grenade (or the secondary fire of the
  submachine gun) into the two towers. There are some agents there you need
  to get rid off. Once they're dead, it's time to deal with the sniper. Go
  back to the marines and go through the entrance. Stay low and seek cover
  all the time. The sniper is in a high position in front of you. Inside a
  building, you'll find a ladder, climb it up and take out the sniper, you
  get a sniper rifle now. There are three entrances to continue now. One is
  blocked by two trip mines above each other (uncrossable) and another by
  two trip mines after each other. The third one is an easy passage, it's
  near the position of the sniper, just past some barrels. It may seem
  tempting to take the easy way, but all the black ops agents will now
  you're coming then. On the other hand, it's not possible to blow them up,
  no matter how far you're standing from the explosion, you'll always die.
  So, the entrance with the two trip mines above each other is not an option
  This is what I did: go to the trip mines that are after each other. Duck
  below the first one and jump over the second one. It doesn't seem to be
  possible to get past the crates. Jump back over the trip mine and then
  jump ON TOP it. Next, jump on the explosive crates and from there, jump
  onto the garbage bin. Now you can get past the crates.

  Take out the two black ops agents in front of you with a grenade. There
  are a few more, but you can all take them by surprise because they don't
  suspect you to come from there. When they're all dead, search the crates
  for some energy cells. There also is a sniper rifle lying on the ground.
  Go through the entrance to the left then. Turn left and you see some
  black ops agents fight a shock trooper. Let the alien finish them off,
  then take out the alien. Search the back of the truck on the right for
  some ammo. Go up the platform on the left then and down the manhole. You
  reach one of the trickiest parts in the game, I've spend a lot of time

  You're now inside a labyrinth and there are a lot of voltigores here,
  more than your displacer can handle. First save, find your way through
  the maze, load and play the game for real then. Take out all the
  voltigores. When you're out the maze, you're inside some water. Climb the
  ladder to the right and a lot of pit drones will appear. Run to the
  entrance to the right and pull the lever. Do the same at the other side.
  In the meantime, just ignore the pit drones and make sure you don't get
  hurt too much. You have to do this because the drones just keep on coming
  otherwise. Take out the rest of the drones then. Search the crates for
  some medikits and some RPG (you'll need it). Go through the entrance to
  the other side and you'll in another maze. Take out the voltigores with
  your RPG, satchel charges, displacer, ... Eventually, you will reach their
  nest. Take out the little ones (they're NOT cute, so it's OK). Finally,
  you can leave that damn maze. Go up the ladder and some marines will
  recognize you. They will cut the grate and you can leave the sewers.
  First, grab all the ammo from the shelves, then order them to follow you
  if you want them to help you.

  Now, there's only one path you can follow are there are lots of voltigores
  and shock troopers. You will need to use all your explosives and spores to
  take them out. They don't keep respawning, you just have to keep moving on
  and secure the area you just passed. When no alien is alive, you'll see a
  big door that reads "confined space" with an entrance. Get inside. It's
  pretty dark, so you'll need you night vision. Proceed to the next area, a
  huge monster, the Gargantua, awaits you. Look to the far wall in the back,
  there are some alien plants there, so use your barnacle gun to get on the
  other side at once. From there, take out the shock troopers that appear.

  Two marines are fighting the Gargantua, but the bridge has been wired.
  Light the fuse and an explosion will kill the Gargantua. Walk to the gap
  in the bridge, there's a pipe to the left with a hole in it.  Jump inside
  the pipe and walk to the right, it will cave in and the flow brings you to
  a new area.

  3.10 The Package

  Follow the flow. On the left, you see a grate, but you can't break it.
  Follow the flow a little further and go left then as soon as you can.
  There's a broken grate. Get through it into the water. Turn around and
  look above you, there's a dead marine there. Get the shotgun ammo. Swim to
  the shore and you find some new squad members. Move forward and take out
  the black ops agent in the water. There's one with a sentry gun on the
  other shore. Order you squad members to wait and use your sniper gun to
  shoot the agent from behind a rock in the shoulder. Proceed to the other
  shore then and secure the area. To the right, there are more agents, they
  are usually hiding under water and they're positioned too much to the
  left to take them out with the sentry gun.  Take them out. Then, return to
  the sentry gun. There's a big chance some more black ops agents will
  appear from the shore you came from. Take them out with your sentry gun,
  then follow the water area, to the left of the wreckage of the helicopter.

  This is a bit tricky. In the back, on top of a building, there is a black
  ops agent with a mortar launcher. You cannot take him out with your sniper
  rifle because there's some glass shield protecting him. Leave your squad
  members behind and run straight at him. He will miss you as long as you
  don't stand still and keep moving forward because he doesn't aim for your
  movement position. Go to the right of him and get on the platform. From
  there, you can take him down with your sniper rifle. In the crates, you'll
  find some ammo for your RPG. Stay away from the building in the middle.
  As soon as you approach that area, three shock troopers will appear. Go to
  the building to the right of the ordinance area. Enter the building and
  take out the black ops agent to the right, down the stairs.

  Listen to the radio, a marine is trapped by black ops, but he'll open the
  bunker doors at the other side of this area. Go back outside. Some black
  ops agents will start firing at you. Retreat inside the building. Once
  you've showed your face, the agents will approach you. As soon as they
  appear in front of the door, take them out with the secondary fire of your
  shotgun, but watch out for grenades. Run to the other side of the area,
  straight forward. One of the double doors of the bunker has been opened.
  Get inside the stockage area. Get on the crates to the left. From there,
  jump to the right, between the two pipes in the back of the room.
  Follow the red light into the new area. Go up the stairs and turn right.
  Take out the black ops agents and search the crates for some items.

  Go to the other side then, some agents will await you. Take them out and
  follow the stairs up. Go through and you can use the mortar launcher
  yourself now. First take out all aliens, then aim to the very left and
  high to shoot the stone walls that surround the building to the left.
  Shoot the aliens that appear and run to the building then. Go through the
  door and enter the next area. There's a voltigore here and a lot of
  shock troopers. Take them out. A black ops helicopter will fly over and
  fire at you. Use your RPG to take it down, it gives a really nice
  explosion. Enter the entrance to the right then and kill the shock trooper
  inside. Proceed to the next area.

  Enter the back of the truck and get the power cells. Go to the left and
  get the ammo. Climb the ladder. Now jump on the black tap on the roof,
  then on the box and from there on the other roof. Proceed and go down the
  ladder then, you're past the fence now. Crouch under the big door and go
  through the door on the left. Turn off the power and return. Climb the
  ladder. Look down, there's a wire from one roof to another above the
  truck. The power is turned off now, so it's safe. Cross the gap over the
  wire to the other roof. Get the medikit and walk to the box in the back.
  Get on top of it and then inside. Drop down into the ventilation shaft.

  Kill the pit drones, go down then and you'll get a lot of enemies to
  battle, about five shock troopers and a voltigore. Take them out. Walk
  forward and a few black ops agents will descend from the ceiling. Take
  them out and walk to the back then. Destroy the crates to the left for
  some items, you'll need them. Go up the jeep then and talk to the security
  guard there, he heard the black ops talking about a bomb. Follow the
  tunnel and enter the next area. Take out the black ops agent guarding the
  door with your sniper rifle. There's another one running around too. Walk
  to the door. The security guard won't let you in, because the bomb is
  armed. Walk past the fences to the left, two black ops agents are working
  on the bomb. Take them out with your sniper rifle and use the "use" key
  then to disable the bomb in the back of the truck. Return to the door and
  the security guard will let you in. Go to the right. Get some items from
  the shelves and ride the elevator down.

  3.11 Worlds collide

  From the start, there are more than ten black ops agents and sniper babes
  that await you. Stay close to your starting position and try to take them
  out one by one. If you get to chance to kill two or three at once with a
  grenade, don't hesitate. Throwing a grenade won't work, because they will
  avoid it. You need the secondary fire of the submachinegun or a quick
  satchel charge. When they're all dead, run to the left and take out the
  agent behind the sentry gun. Go to the right of the sentry gun and use the
  crates there to get on the platform. Walk to the back and drop down. Kill
  the black ops agent. Now, look to the right, crates are passing by. Look
  to the wall a little to the right inside the tunnel, there's a small
  alcove you can enter. As soon as a crate has passed, run inside the tunnel
  and stand in the alcove for a short moment. As soon as another crate has
  passed, run to the entrance on the other side. There are some black ops
  agents here, on the platform above you, so throw a quick grenade to take
  them out. Go up the elevator and search the crates behind you. Go straight
  ahead then.

  In the back of the room, you see some crates that form a stairway. Use
  them to get as high as possible. Proceed on top of the crates and jump to
  the right inside the entrance. Move forward slowly and look down, there's
  a big fight going on between the black ops and the aliens. Wait until one
  side has lost. Jump from swinging crate to another one and land on top of
  a big crate. From that position, try to take out all resistance with
  grenades and satchel charges. When all resistance has been eliminated, run
  up the slope to the left then. Search the crates and the door on the right
  will open. Talk to the security guard, he has seen a terrible monster.
  Search the shelves and the crates for ammo, you have to be fully equipped
  now. There are also some stations for health and HEV. Enter the elevator
  and press the button to ride it down.

  When down, a force will push you back. There's also something
  strange about the gravity. Never mind that and walk forward. Go down
  the stairs an open the door. You reach a room with a ladder and a rope.
  Use the rope to get on a higher level. Look to the left there, there's a
  healing pool near the wall. When fighting the boss, you'll get some
  serious damage. Return often if needed, there's no time limit on fighting
  the boss.

  Proceed to the next room. There's a big purple portal here and sentry guns
  on both sides of the railing. Go to the sentry on the left and wait until
  something really big appears from the portal, it's the final boss and he
  looks really mean. There are two weak spots on his body, though, they
  light up a in yellow (I think they are the eyes). Make sure to avoid
  contact with the green toxic waste it breathes. When you shot one eye,
  walk to the sentry gun on the other side and shoot the other one. When
  both eyes are hit, a spot under his belly will open up and you see a
  purple ball, this is his vital spot. Try to hit the purple ball as much
  as you can with your sentry gun, it's the only way to kill it.
  Alternatively, you can also use the RPG from some distance to hit the
  purple ball. You don't have to stand to close to then and it's easier to
  aim (added by CjayC).
  Now do the whole process again. Don't forget to return to the health pool
  when your health is low.

  Now and then, the purple ball spawns a shock trooper, so make sure to take
  that one out first. The second time you hit the ball, the monster will
  start to destroy a part of the bridge you're standing on and the ladder to
  reach the left sentry gun from the ground. From then on, you'll have to
  use your barnacle gun on the organic structure on the other side to get to
  the left sentry gun. Do the process again until the monster will retreat
  and explode.

  3.12 The end

  You get to know the man in the suit a little better and the game ends as
  good for the "hero" like Gordon Freeman in the original Half Life. Too
  bad, Shephard :(

IV New monsters

  Not all monsters are new, so I suppose you're familiar with the ones
  from the original Half Life. I'll give a brief overview of the new 
  monsters in Half Life.

   Zombie Grunt
     An unfortunate grunt who got himself headcrabbed and turned into a
     zombie. He's much tougher than the zombie scientist. Its gaping chest
     wound opens up and he sticks his hand inside to pull out an acid globs
     to whip at you...  ewww. Like the zombie scientist, you can take them
     out with your knife or your wrench. A few bullets from your pistol in
     his head work fine too. (Thanks J. Anderson)

   Pit Drone
     One of the new Race-X aliens, a race of aliens that appeared in Black
     Mesa after Gordon left for Xen. Pit Drones can use their claws for
     close combat and have the ability to shoot spikes from their forehead,
     which regenerate in time. The spikes are shot at a fast speed, so
     you'll have to be quick to avoid them. Usually, they are not so tough
     to take them out, one blow of your shotgun at close distance will take
     them out.

   Shock Trooper
     This a very nasty alien from the X-Race alien breed. They can create
     portals to call reinforcements. A shock roach is attached to their side
     and they use it to fire. They fire at a very fast firing rate and they
     can take a lot of damage before they die. When it's dead, the shock
     roach leaves the body of the shock trooper and attacks you.

     This is the toughest of the 'regular' aliens. It looks a bit like a
     huge spider and it has two claws that do serious damage. They can also
     spit some purple electricity. When they die, they explode and do some
     radial damage, so don't stand too close.

V Cheats

  5.1 Easter eggs

  * When you approach the Boss of Opposing Force, there is a Weird Mumble
    jumbo of sounds. When played backwards they say "To win the game you
    must kill me Randy Pitchford". Just like when you beat Doom 2 who was
    made by John Romero the Co-Founder of Doom. Like ID software, Randy
    Pitchford is the leader of Gearbox Software who made Opposing Force.

      Note: An easy way to play the sound is open the pak0.pak file with a
            program like PakExplorer and search for the sound dsbossit

    I've put the files online for download to save you the trouble.
    Download them here:

      - original file: http://members.xoom.com/Larian2/special/dsbossit.wav
      - reversed file: http://members.xoom.com/Larian2/special/dsbossit2.wav

  * Just like in Half Life where the names of some of the people who made
    it were put around the lockers in the locker room, the names of some of
    the people who made Opposing Force are also in certain places e.g. at
    the start of the boot camp level look at the names on the boxes beside
    the beds. 

  * The 'trash compactor' in the "Pit Worm's nest" level is right out of
    starwars (look at the doors and the pattern of lights above the doors)
    (Thanks J Anderson).

  * Start the "boot camp" and type /noclip in the console to walk through
    walls. Go straight through the floor then and you reach a room with the
    hidden message "DMM 1999". DMM 1999 refers to David Michael Mertz 1999,
    the creator of the bootcamp.

  * If you're really curious about the man in the suit, you can use the
    "noclip" cheat code to walk throughs walls and doors to follow him.
    You will see him adjusting warheads and you even can take a look
    inside his briefcase.

  * It's possible to take a good look at Freeman (I'm not talking about the
    various pictures on the wall). At the beginning of Level 5 'We are not
    alone, listen carefully, you'll hear a scientist encouraging "Freeman"
    to hurry. That's Gordon Freeman, the character players portrayed in the
    original Half-Life! Try leaping into the orb to follow him to Xen.
    Unfortunately, you don't land over a platform like he did. For more fun,
    switch to noclip mode and warp inside. You can get a good look at
    Freeman then.

  * Use PakExplorer to open the half-life\gearbox\pak0.pak file. Go into
    the gfx\env\ folder. There is a texture, named @hackup.tga or
    hackup.tga which says: 

      ALL DAY LONG. 

      THIS SONG." 

    It's rather funny, so I searched the game for a place where the texture
    was used. I found the location, you can see it when you're talking
    to the G-man after finsihing the game. You can move when talking to him,
    so do the following. First type "chase_active 1" in the console, then
    type in "thirdperson". You get a better view of the environment now.
    Just look up and you'll see the texture.

    The poem is an adjusted version of an Adam Sandler poem. All I remember
    was it was about a janitor and the word "hack" was originally "mop" 

  * This easter egg gives some problems, becaue I don't recall in which
    level I found it. Anyway, somewhere, there's a filing cabinet/desk
    lying on the floor next to a picture of Gordon Freeman. If you crouch
    and look at the desk, there's a picture of two kids. I assume they're
    the kids of one of the programmers. 

  * The Boot Camp is linked in a nice way to the actual game (easter egg
    exposed by Liquid CsHO)

     - When you see the push-up guy... look up to the room to your top
       right... G-man is talking to the Sergeant/Colonel (whatever rank)
       that talks to Cooper (Cooper... Do you copy.. we are pulling out...
       if you have any more targets mark them witrh......). Therefore...
       he's in on it too.

     - The marines by the osprey are the same marines that company you on
       the ride in... (they don't talk in this scene).

     - When you pass boot camp.. the Drill sergeant says "congratulations
       soldier... ...Now report to duty!!"... then you leave on the
       helicopter. If you use the noclip before starting the training, you
       can reach an area with a helicopter, so you can see the marines
       you'll meet later on the game getting on the helicopter already.

  * The easter eggs just keep on coming and this only is really weird. Open
    up the OPFOR.DLL in the /gearbox/dll directory using wordpad, and do a
    search for "lime". This is what the story says (this is a cut & paste):

      .the half-life of lime jello.nuclear bedtime story...crazy
      customizable..programmer's head on a stick....frictionless, massless
      mormon...put it in your report, bill.i don't need the influence..i'm
      coming out of the booth.in the middle of a storm....it tantalizes me
      so.you are my favorite thing...i leave the windows open....and fed
      you to the chickens.candy corn chicken fetus....the silhouette of a
      dog.guns exploding all around...a rising column of smoke....you don't
      jump like a monkey....i have to call chuck....rebel boat rocker...
      colostomy bag...walking in memphis..exploding midget....white cotton
      panties....nub technology..anonymous nub...more bunny justice..evil
      evil boy...you have been a fool....do not send me porn.i must escape
      it....those creamy white thighs...keeping us all cool.air
      conditioning....so what if I sweat..fresh air is so sweet...live mice
      sit on us.digital squirrel....liquid banana...peas and hominy.
      miscellaneous...gravity assist..random tuna head....some quick goat
      thinking....a velvet codpiece...let's tease the weasels. nice
      vomiting spell.a specific dick.the growing yodas...radsuit_finished
      origin..Master was null or not a master! ...violence_ablood.
      violence_hblood.NULL Ent in UTIL_PrecacheOther .CSaveRestoreBuffer
      :: TokenHash() is COMPLETELY FULL!...Invalid function pointer in
      entity!.Bad field in entity!! ..Bad field type .Can't save more than
      %d entities in an array!!! ....CSave :: BufferHeader() size parameter
      exceeds 'short'!.Save/Restore overflow!..Restore overflow!


   This is really crazy, but it's a great easter egg.

  * If you don't want to search the opfor.dll file, it's also possible to
    get a poem while playing. During gameplay, bring down the console and
    type "haiku" (without the quotes), the game will treat you a strange
    poem (a random generated Haiku from the opfor.dll file).

  * In the first level after the crash, a zombie throws a scientist
    through a window. If you run around the zombie into the lab, you'll see
    a computer with an ultrasound image. That ultrasound is of Randall
    Steward Pitchford III, the son of Randy Pitchford (the leader of
    Gearbox Software who developed Opposing Force). He was born on
    January 8, after the game shipped!

  * There's a computer in the room where you meet Otis for the first
    time that looks like it's running MS Windows. If you use the keyboard
    five times, the computer will crash with the "blue screen of death."

  * If you use the self-teleporting alt. fire of the displacer while
    you're still on Xen (right after you first get the weapon), you'll be
    taken back to the hazard course on Earth. On the corkboard on the wall
    there's a picture of Gearbox designer, Rob Heironimus. He's got Easter
    Egg shells in his eye sockets!

  * In the Pit Worm's Nest the "gearbox" and "valve" indicators are
    obviously a reference to the creators of the Half-Life games.

  * Johan sent me a strange bug\easter egg in the game, this is what he
    mailed me (thanks!):

      Hi, my name is Johan and I just read your walkthru of Opposing Force.
      I've already finished the game but I wanted to what else there was
      that I've missed myself. One thing I've discovered that you didn't
      have in your guide was that you at one point in the game actually can
      "meet" the black man thats always on the wrong side of the bullet
      proof windows.

      I suppose you know that the displacer gun secondary fire teleports
      you to different places in Xen or Earth depending on where you are.
      This can be used at one point to get behind the bullet proof glass
      and inside the same room as the black man.

      After you've disarmed the bomb in "The Package" the guard lets you in.
      Walk past him and to the left. Through the glass you see the black
      man, tampering with the bomb you've just disabeled. The bomb later
      goes off after you've killed the big boss at the end. If you use the
      displacer's secondary fire near the glass, you are transported to Xen.
      You should see two aliens here standing in a pool and some weird ball
      floating around in mid air.

      I killed the aliens and explored the area a bit. All the holes you
      see in the cave, you can't get in to. I didn't know what those egg
      things are called but I used the little one to get to the medium sized
      one and then into one of the holes. That should be an easy jump, but
      when you reach the hole, there's an invisible wall blocking further
      movement and you fall down. I suppose this is an bug in the game, or
      just bad programming (which is the same, when I come to think of it).

      Anyway, when you walk back to where you come from you comes to a
      crossing where you take right to find the teleporter back to earth.
      When I entered something weird happend. I was teleported back to the
      bomb truck. I've did testing and that's the place you are teleported
      back to if you use the displacer gun before you enter the room with
      the guard. If you walk to the back of the truck you will see the
      black man there. He can't be killed of course and there's no way
      out of there here, so you've got to reload an save game if you want
      to move on.

      This must be an bug in the game, or maybe an unexpected easter egg.
      Just thought you should know.

      Thats it, thats that.


  5.2 Cheats
  There are a lot of problems with the cheats, sometimes they all work,
  sometimes half of them work, it depends on the what patch for Half Life
  you're using, what version of Opposing Force you installed and
  apparently a lot of luck.

  Go to Windows Explorer. Right click on the hl.exe file (from opposing
  force). Select "create shortcut". Right click on the shortcut. Select
  "properties". Go to the Tab "shortcut" (if not selected already). Go to
  the line that reads "target". There add -dev -console -game gearbox
  behind hl.exe. It will look similar to this now:

    "hl.exe" -dev -console -game gearbox

  Start the game with the shortcut, it will take you to Half Life: opposing
  force at once. From then on, you access the console using ~ (the key
  above Tab and below Esc). The following commands are available in the
  console then:

     HAIKU: Random generated poem
     NOCLIP : Walk through walls and fly
     /GOD : God mode
     /NO TARGET : Enemies ignore you
     /GIVE xxxx : Give item xxxx
     /GIVE AMMO_556 : ammo for M249
     /GIVE AMMO_762 : Give ammo for Sniper rifle
     /GIVE WEAPON_X : Replace X by any other weapon names below to get
                      the desired weapon:

         * GRAPPLE 
         * KNIFE 
         * PIPEWRENCH 
         * EAGLE 
         * M249 
         * SNIPERRIFLE 
         * DISPLACER 
         * SHOCKRIFLE 

     /MAP xxxx : Replace xxxx with one of the map names below to warp to
                 that level:

         * OFBOOT1 
         * OFBOOT2 
         * OFBOOT3 
         * OFBOOT4

    sv_cheats 1 : After typing this in the console, wait until the game
                  loads a new area of the game, then you can use the
                  following cheat to obtain weapons & ammo: IMPULSE 101

                  You can use this cheat again once you're has depleted.
                  Don't forget, using the IMPULSE 101 cheat xill gtive you
                  all the weapons from the original Half Life, not the
                  ones from the Opposing Force walkthrough. This means
                  it's possible then to use weapons (like the Hornet gun)
                  that were not ment to be in the game.

  5.3 Xen Locations

  In Level 5, (we're not alone), you will teleport to Xen where you can find
  the displacer weapon (read the exact instructions and location in the
  walkthrough). This displacer weapon allows you to teleport any monster
  to Xen, but on some specific places of the game, you can also use this
  weapon on yourself to teleport yourself to Xen. You cannot do this
  anywhere, only on the locations written below.

  The locations often contain some items or a health pool, so they're
  very useful, but they also serve as fun locations, hidden secrets in
  the game. To use the displacer weapon on yourself, you will need about
  60 cells. The hidden areas in Xen all have portal. Walk through the
  portal and you will return to earth where you teleported.

    We're not alone (while on Xen)
    After collecting the displacer from the scientist that falls to death,
    use it at once. Normally, you would transport to Xen now, but since you
    are on Xen already, you will be tranported to Earth, to the hazard
    course of the bootcamp. There, you have to take out some alien slaves
    (they try to attack the instructor hologram and that's quite funny,
    then do a bit of the course and smash the window to the right. Step in
    the teleporter and you will return to Xen.

    Crush Depth (beginning)
    Use the displacer in the beginning and you will be teleported to
    a (circular) area with a few bull squids and armor pickups. 

    Vicarious Reality (beginning) 
    If you need a full heal and can't find a health station, take a trip to
    Xen here and find a blue healing pool as well as a trapped scientist.

    Vicarious Reality (at elevator shaft)
    This takes you to a Xen world with platforms and a flock of alien birds.
    Leaping to the different platforms could gain you an ammunition pack
    and some armor.

    Pit Worm's Nest (beginning)

    This teleports you to an underwater Xen location with health and armor.
    What is that coming out of those tubes near the surface?

    Pit Worm's Nest (gearbox switch)
    Save your game before venturing here. You plunge to your death as you
    appear in midair. If you look closely as you fall, you'll spot a
    scientist dangling from one of the platforms. At least he's still
    holding on.

    Foxtrot Uniform (beginning) 
    Use your displacer on yourself here for a safe enclosed area with a
    healing pool.

    Foxtrot Uniform (alien/Black Ops battle)
    When teleporting here, you will in an enclosed area with a bullsquid
    ready to attack.

    Foxtrot Uniform (near the end of the level)
    Here you teleport to a dark set of platforms with a dangerously long
    fall to the return warp orb.

    Foxtrot Uniform (Voltigore labyrinth)

    I haven't tried this one myself, but I'll trust Emilio Hastings who sent
    me this it will work.

    After the explosion cuts off the way back up the ladder, the only way 
    to go is into the maze. Facing the skeleton, pull out the displacer gun 
    (you have to have enough energy to get to Xen or it wont work). Start 
    running through the maze, when you get to the first intersection where
    the tunnel splits (choice of going left or straight) go straight. As
    soon as you pass the tunnel on your left a voltigore will start chasing
    you, so as you pass the opening you should activate the displacer to
    take you to Xen. When you get into Xen, you'll be taken to a wide open
    area (simular to ones previous). Kill the two bull squids and go to the
    portal back to Black Mesa. When you go back to black mesa, you should
    end up in the part of the maze where you are supposed to close the
    hatches on the drones. Ending up here completely bypasses about 5
    voltigores and saves considderable ammounts of ammo and health.

    The Package (beginning)
    Here you'll find a nice blue healing pool and a very happy scientist.
    This is a rather useful location when you're hurt.

    The Package (outside at wire) 
    This teleports you to another underwater area with some health and

    The Package (end of level) 
    This leads to an enclosed area resembling the one seen during Foxtrot

    Worlds Collide (beginning) 
    This takes you to a Xen area with bullsquids and a small stream.

    Worlds Collide (inside boss room) 
    If you're struggling for ammunition, head to Xen from here. You'll find
    a beautiful sky, some platforms, and an ammunition pack


VI Links & Greets

  If you're looking for a good Half Life site, there's only one address:
  Planet Half Life: www.planethalflife.com. They have every single piece of
  information you're looking for.

  Thanks go to Johan ([email protected]) for sending me an
  incredible easter egg about the main in the black suit.

  Thanks Jason Suggs for correcting a little mistake in the walkthrough

  Thanks Crash Easton for the neat trick

  If you have any questions, you can always mail me on
  [email protected]

VII Author

Just in case you think you already saw my name somewhere else (what an
excuse to do some self promotion! :) )

Author: Stijn Bolle
E-Mail: [email protected]
Guides written:

  * Aliens vs. Predator (walkthrough\guide)
  * Baldur's Gate (secrets)
  * Discworld (walkthrough)
  * Half Life (multiplayer guide)
  * Half Life: opposing force (guide\walkthrough)
  * Half Life: opposing force (dutch translation)
  * Lands of Lore 3 (guide\walkthrough)
  * Monkey Island III (walkthrough)

VIII Legal Notice

None of this file may be copied or reproduced without the explicit
permission of the author. This guide may be added freely to any guides
collection site as long as you mail you the url, you don't alter anything
and you give me full credit. If you're not sure, just mail me on
[email protected]

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