Well we managed to successfully navigate through Black Mesa's gratuitously violent industrial section and now we're back into civilized territory. This level takes place in the labs of Black Mesa where aliens specimens are being studied, hence the name. I hope you're not too used to the absence of things to shoot, for the amount of enemy activity in this level is more than enough to make up for the last one. Speaking of enemies, you will soon be introduces to a formidable alien foe who will continue to make appearances throughout the rest of the game. But enough of the introduction, let's get into the game.
Back in Civilization
The beginning of this level doesn't bother taking it easy on you, but throws you right back into the fray. The ladder at the end of this passageway leads right up into a pen of Houndeyes. Smash the grate and take care of the Houndeyes however you can (the satchel charge or pistol work well here). When you have established your place as top dog, check out the electrified fence. There is a little electrified ball connected to a console on the wall. Shooting either of these until it breaks will grant you freedom. There's a first aid station for you to use if the green goo got the best of you in the previous level.
Beyond this room, you will find an Alien Grunt trapped in a containment tube and a locked door. In order to unlock the door, you must break the glass guarding a red button which will also release the Alien Grunt. You can either shoot him or run for your life, but either way, head through the door to a special room with a cage of Headcrabs in the center. Enter the booth and press the button. Gape in wonder at the awe inspiring power that is unleashed at the simple press of a button. When all that remains of the creatures are chunks, exit the booth and open the door. There is a marine standing right outside the door, so lure him in, run back into the booth, and press the button. You almost feel bad for the guy as he scrambles around trying to figure out what to do before being destroyed. On the bright side, you now have a assault rifle. Around the corner, you will find a security guard. He'll tell you how to get out of here. Listen to him and have him follow you around the corner.
Testing Facilities
Continue down this hallway to the main entryway. There are two marines in this room that can be taken care of easily with an assault rifle grenade or a few .357 Magnum shots. When these two are down, two more will enter, one carrying a shotgun. Greet them with a few bullets, then use the HEV station to charge up your suit. Go straight across and up some stairs to a balcony looking over the area you just visited. Leave the guard behind, then head into the next room, which is similar to the first one you encountered. Press the button to release a bunch of Headcrabs, then head into the booth to fry them. Afterward, go into the alcove the creatures came from to find a crossbow and some Snarks. Go back and grab the security guard and head into the next room. Take a right at the fork and take out another pair of grunts.
You will eventually get to a large room with a bunch of computer columns in the center and some laser mines blocking a hallway. Ignore the laser mines for now and just grab the batteries. Take the security guard up a ramp to a balcony that overlooks the larger room. From here, use your pistol and take out the laser mines. See why it was a good idea to wait? Try to look inconspicuous for as long as possible, although it is likely that an enemy of one side or another will come up to pay you a visit. After the battle, head back down and clean up any survivors. Then head through the doorway that the laser mines were guarding.
Be wary, for a grunt will try to ambush you down this hallway. Eventually, you will get to a large doorway with a pile of crates blocking the way. There is a laser mine aimed at one of these boxes, so save the game before attempting to clear the path. Through this way are several cages of Headcrabs that will break the glass and attack you as you pass. Take the first path to the left and up the stairs. At the top, you will see an ongoing fight between bullsquids and marines. Wait until the battle dies down before going out into the hallway.