After the nice lab explosion, you appear in a water filled pit on another world. Press up to swim to the top and up and right to get out. Go right and kill all those little beasties in the next two screens. Then keep going right. At about halfway thru the third screen over from the water, a beast will appear. Run left and just keep running. At the ledge, jump on the rope. You'll swing back right. Now keep running right. After you run into the alien, just watch and do nothing.
OK, now your in a cage. Start swinging left and right. After it lands on the alien, pick up his gun. Run two screens right and kill the alien. Move to the right side of the screen and shoot two aliens as they come from the left. Then go to the next screen to the right, and your bud should be trying to open the door. Set some shields (hold down spacebar until a little glow appears at the end of your gun, then release it). Set like 2-3 shields to be safe. When the doors to your right open up, follow your friend right. Take the elevator to the bottom. Walk into the next screen to the left, shooting as you go.
The aim is to kill a guy as soon as you enter the room. After you kill him, shoot the little light on the wall. Then take the elevator up one floor. Go left and blow a hole in the wall (hold down fire until a large glowing ball appears on your gun, and release it). Then run left and stand over the teleporter (hole in the floor) and push down. Then continue to run left. Go up the next teleporter. (Make sure your bud is with you). Go left through the door. Your bud will come behind you and open a hole in the floor. Go down it.
OK, you're rollin' in the pipes. I'll tell you the path, you just avoid the steam. Left all the way. Fall. Right. Fall. Right. Fall. Left. Fall. Right. Fall.
Go left and charge you gun. Shoot through the three walls (overload gun technique). Run right. Shoot the alien on the bridge, and then move to the edge of the brigde. Jump out and you'll land on a ledge. Shoot a hole in the wall.
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