Back to Ultimate Doom
As soon as you begin the level you’ll be attacked by a Demon. Take it down and kill the other roaming enemies. Explore the three southern alcoves where you started for some ammo and a medipak.
This level is essentially one large circle with a central area. I like to go anti-clockwise to pick up the Backpack and Beserk pack first. Make your way around to a corridor leading north. Take out the Baron and then go through the small passage to the east which leads to Secret 1. Follow the path around to a room with a lowered floor. Pull the switch to raise up the floor. Take out the Demons and continue around to Secret 2 with a Backpack and other loot. Follow the path down to the slime pool for a Beserk pack.
Go back to the main area and take the next left. Jump into the slime pool and pick up the Chaingun around the corner for Secret 3. Go back and follow the corridors to the north and then back west. When you open the next door to the west you’ll be attacked by another Baron and a few smaller enemies. Take them out and enter the room to the north.
The blue door is here but you’ll need the key from the central area. Step behind the small structure that looks like an altar and Secret 4 will open. Inside is a Computer Area Map. Move closer to the other wall and it will open automatically. This is Secret 5. This time two Demons will rush out.
Complete a lap around the level by heading around to the west and back to the start. Take the stairs up to the central section. When you push the skull button the central pillar will lower, revealing a Shotgun. You’ll be attacked by a Demon from the left stairs.
Head up the stairs on the right side and explore this area for the Blue Key. Go back and head up the stairs on the left side. The northern section of this upper area drops down to a lava room. Inside you’ll find Secret 6 with the first BFG of the game. Around one of the other corners in the lava room you’ll find a Soul Sphere.
When you’re done exploring make your way around to the blue door and go through. Kill the many Imps and head through the exit to complete the level.