Go through the door and then door on the left. In the first area you are going to have three Imps. If the timing isn't quite right just use the Double Barrel again. On Nightmare a Forgotten One, a zombie, and a Maggot will spawn in that room. *** Spoiler - click to reveal ***On Nightmare there will just be two Soldiers. When you go through the only other unlocked door an Imp will be waiting for you and leap out at you. You are going to get a fair amount of medium - strong enemies to deal with including a couple of Commando Tentacle Soldiers. Blow him to pieces with the Double Barrel. For the zombies just blast them as they come at you with the Double Barrel. Wait at the locked door and pick it off with the Pistol as it comes down. As you enter this next area, don't go forward like it appears you need to. As you enter a zombie and a Soldier will jump you. *** Spoiler - click to reveal ***You're going to run through the room until you go up both staircases into Upper Service Hall. On the left side of the machine is an empty holster (the other side has the same holster but something in it). On the right will be a ladder, climb down it. Do the same to these Soldiers as you did for the previous room with rockets. Go around the corner to find a health station. For the Forgotten Ones just use the Grabber. For the first Arch-Vile just use the Soul Cube and mop up any Imps it spawned. If you leave that desk and go left there will be a dead body at another computer console. If enemies aren't spawning or the bot isn't moving start following it. As the Imp and Wraith spawn, use the Double Barrel on them. When you do go down the steps an Imp will come where you came from. If you get this right you can hit all of them with the Shotgun they spawn. As the Commando runs at you blast it with your Double Barrel. *** Spoiler - click to reveal ***Wait by the lift. Now, go down the ramp and activate the computer. *** Spoiler - click to reveal ***When you go down the stairs immediately go back up them and a Maggot will spawn in the initial room. Some Forgotten Ones will spawn behind you. Now you will need to restore power to the lift. *** Spoiler - click to reveal ***Wait at the beginning of the room and use the Grabber on the two Imps that spawn.

Doom 3 hell walkthrough