When you press the trigger, the chain gun begins to spin and moments later the weapon starts to fire. Move inside the substation and restart the system. Like zombies, imps often hide in ambush points--in dark corners, behind hidden panels, and even at the entrance to new rooms. The next hall contains a trio of guards. Grab some supplies from this storage area. Sprint and jump to the platform and then onto the red pipe.
Discovering the code and opening the cabinet offers a chaingun reward. Move forward to the entrance. The audio contains the code for the nearby cabinet: 972. Search Banks' office for health and ammo before retracing your steps back toward the lobby. Engage several guards at this point. Be ready to take out a maintenance worker fully zombie now on the other side of the door.
Walking onto the catwalk triggers a few spiders from either side. Ride it to the group of soldiers. Beware of a guard across the way; take him out with the machinegun. It fires a green ball of death that actually inflicts damage to anything in sight as it moves through the air. When facing an imp, maneuver as close as possible and aim the shotgun at the imp's upper torso. Return to the hall with the locked door; battle some guards along the way.
A cut scene interrupts the action; you receive the transmission card. If the z-sec doesn't approach, a grenade isn't a bad option. The shotgun: then and now. The demon is fast and lacks ranged ability; it will charge you on sight and gore you like a bull. The flashlight if you are fast enough or just the pistol usually will suffice. But it's wise to keep the hell knight at a distance.
Don't get caught reloading in a frantic battle against multiple enemies. Back off and blast him with the shotgun. And certainly the rocket launcher has the power to take down the pinky beast. Wait for the rotating platform to reach you, hop on, and get off at the unlocked door. Beware of the maggot that emerges from behind. Check your back for enemies attempting to sneak up behind and perform their own version of the ambush. At medium-range, develop a pattern.
Replace the rod using this computer. Scurry up the ladder, defeat more spiders, and then go left through the transfer bay into the next level. One of the most important aspects of the machine gun is keeping it reloaded. Reach the Enpro Plant as quickly as possible. An imp appears in the next room; shoot him with the machinegun then battle another guard through the new path. Speak with the guy exiting the bathroom and explore inside if you wish. Continue straight into the kitchen area.
Back up to take on the two ahead but remember there's a third behind you. Don't turn corners or enter new rooms with just five rounds left. Three seekers hover around the guardian. Descend a staircase to find a plasma gun resting next to this corpse. Shoot the explosive barrels to obliterate the guard ahead. It's certainly best to save up the ammo for the toughest battles, primarily boss fights, multiple hell knights, or even an irritating arch vile. An imp appears at the room's center and another emerges behind you.
Open the transfer door and enter alpha labs reception. . Also go ahead and duck around the fire for items. If there's more than one, expect them to be at opposite corners of the area, which creates a difficult fight with rockets flying in from multiple locations. Return to the previous room and the opposite exit door.