Level 12: Crater
Back to Final Doom
Open the door and take out the Gunners in the oval room. The stairs to the west lead up to a lookout above the crater and the corridor to the east leads to a storage room with the Blue Door. For now clear out these staring areas and then open the door just south of the oval room. Inside you’ll find the Blue Key.
When you pick it up the back wall will open revealing a Mancubus. Then side rooms will open releasing Demons. Take them out and then clear out the southern side of this map.
When you’re done head back to the Start. On the west side of the oval room you’ll see a part of the wall with a brown stain on it. Open it to be taken down to a lower area. From here you can make your way around to a long corridor. Just watch out for the Arachnotron hidden behind an invisible wall at the other end of the corridor.
Continue all the way along to the eastern side of the corridor. The back wall is a lift that takes you up to the room above. Take out the Gunners and then the Barons of Hell. When you move towards the Soulsphere Mancubus and then Arachnotrons will spawn in as well.
Hit the Switch to leave the room and then make your way to the Blue Door in one of the storage rooms.
First clear out the side walkways and then head down the stairs to the crater. Explore the area and head up the stairs on the north side. Take out the Baron of Hell and grab the Red Key he was guarding.
Now that you have the Red Key head back up the stairs and go through the Red Door on the eastern walkway. Take the lift down to a dark area and clear out all the enemies.
Lower down the door with the blue lights but watch out for the Arch Vile on top of it! Ride the door/lift up and explore either side for Secret 1 and Secret 2. When you’re done enter through the door to the next room.
Take out the Gunners around the pillars and then the Arachnotrons on the platforms.
Once they’ve been killed you can safely make your way to the Exit.