Half-Life/Office Complex

Office Complex
Office Complex is about the size and difficulty of Unforeseen Consequences. You will start to battle one of the most common enemies, the Vortigaunt, and have to fight some Bullsquids (a long with some headcrabs and zombies of course). It takes place in several Black Mesa administration facilities, which of course, have been overrun by the aliens.

When the elevator reaches the ground floor, the doors will open. Take the battery and the medkit (if you need it) that are nearby. Do not walk up to the red double doors just yet, and do not walk past the vent shaft. Wait for the fallen light to kill the headcrabs and then walk up to the vent shaft (but don't go too far past it, or you will take some major damage from the light). The electricity from the fallen light will destroy the vent shaft, granting you a passage. Crouch down and take a right from the vent shaft entrance (we'll go back to the left passage soon). Keep going until you come to another grate, which you must destroy. Inside the room are two scientists, and one of them gets dragged up by barnacle after he gets scared. You can let him get killed by the barnacle if you want, because he serves no purpose. Barnacles will then begin to come through the ceiling, so watch your step.

Go through the doorway labeled 'DANGER: HIGH VOLTAGE' and press the switch inside. This disables power throughout the entire facility (including that dangerous light). Go through the double red doors and back into the hallway. Before we go to the next area, go back into the vent shaft and take the left passage. Keep following the path and it will lead to a fan, where a dead security guard with three clips of pistol ammo lies. Shoot the three headcrabs from behind the cage with your Glock, and then claim the ammo near the dead guard. Exit the vent shaft and go the end of the hall, where you'll have to destroy the window with your crowbar. Crouch jump through the window, and take a left. This is the main hallway. Go to the very end of hallway, past the storage closet. We won't worry about the other rooms for now.

Smash all of the wooden crates with your crowbar as you go down the hall. Be careful though, because behind the largest wooden crate is a sneaky headcrab. I suggest throwing a grenade behind the crate, because the blast will be more than enough to kill one little headcrab. If you don't have any grenades, you'll have to risk being bitten by the headcrab as soon as you go past the crate. Smash the large crate after you kill the headcrab, and then keep going down the hall, which leads to a security checkpoint. Grab the shotgun and shells off of the green box to the right and walk up to the gate, where a security guard is. I suggest saving the game before you walk up to the gate, because we'll need that security guard to unlock the gate (it leads to four boxes of shotgun shells, three pistol clips, and a medkit). As soon as you walk up to the guard, a zombie will emerge from a nearby room. Immediately kill the zombie with two double-barrel blasts to the head (secondary fire, default: Right Mouse Button). Once it's dead, the guard will gladly open the door.

Collect the shotgun shells next to the security guard and have him follow you into the next room. Grab the three boxes of shells, pistol clips, and medkit if you need it. A headcrab will jump from a vent shaft up above, but the security guard can handle it no problem, so just have him kill it. Walk back to the platform and descend the ladder. Smash the crate next to the ladder for a medkit, and the two other crates for one battery. Climb back up the ladder and make sure the security guard is following you. Retrace your steps back to the main hallway and have the security guard wait by the double red doors. Walk up to the storage closet and a zombie will burst from it. Walk back to the security guard and double team the zombie. It should be dead in no time. Grab the two clips of pistol ammo in the closet and have the security guard stand in front of the broken window. He should be able to kill the headcrab that's in the next room.

Now have the guard wait in front of the window and crouch jump through the window. This room is completely flooded with electrified water. Jump on the white table in front of you, and then do a diagonal jump to the sink on the right. It's alright if you fall into the water, because it does very little damage (just make sure you go back on a surface right away). Do a small jump to the health station and use it if you have to, and then jump to the small lightswitch that's to the right. Press the light switch and the water will no longer be filled with electricity.

Walk up to the vent shaft nearby and turn on your flashlight (default is the F key). Smash the grate with your crowbar and immediately take out your pistol. Shoot all three of the headcrabs that are up ahead and then crouch jump into the shaft. Now make sure you stay crouched, because as soon you stand up, a fan will kill you instantly. Keep following the vent shaft until you get to another grate. Destroy it, and then go through. You will fall into the hallway that was behind the locked double red doors. Open both doors and make the security guard follow you again. Go back to the double red doors and walk down the hallway. Two headcrabs will fall through the ceiling, but just have the guard kill them both. Have the security guard wait near the single red door in the corner (make sure he's not directly in front of it). Now push the large blue crate directly under the gray ladder that's up above (where the headcrabs came from). Push the smaller crate next to the big one, and then jump from the small crate to the large one. Look up at the ladder and jump, and then climb up to the top. Jump off to the left and go up to the grate. A headcrab will be nearby, so kill it immediately. Destroy the grate, but don't drop down yet.

Wait until a scientist comes and gets mowed down by a turret. After the scientist is killed, a headcrab will come. Wait for the turret to kill the headcrab, and then look at the large blue crate below. I recommend saving the game at this point. Now jump down and quickly crouch behind the blue crate. Keep pushing the crate foward until you're under a platform, where you'll see a switch. Press the switch and the turret will be disabled. Smash the wooden crate that was next to the blue one for a clip of pistol ammo, and then go through the doorway next to the dead scientist. To the very right of the room is a shotgun and box of shells, and on some shelves nearby are two pistol clips. Now open the door at the end of this room, which will lead back to the security guard you left behind. Have him follow you back to the turret room, and then have him wait in front of the large passageway on the left. Equip your grenades and walk down the hall, where you'll notice six headcrabs are waiting. Throw a grenade into the center of the group and run back to the security guard. Have him follow you through the hallway, where he'll pick off any survivors. Now go up the stairs, where another security guard is shooting some headcrabs.