Walking to the other side of the arena will teleport you up to a nearby ledge containing the BFG9000. The most infamous encounter of the level is to the northeast. The yellow-key switch to the northwest will gain access to two encounters needed to progress. On the east corner there is a switch that will open up a teleporter for you to escape. The closest one will teleport you to the southeast arena containing the yellow key. To the southeast of this area there are yellow platforms that, when stepped on, will lower two teleporters. A switch is to the south which will lower the bars, allowing access to the northern part of the complex.
Keep following the stairs up to the northwest balcony. Follow the stairs to the right, drop down when you can, and take a lift to the right (accompanied by a megaarmor). An optional encounter containing the super shotgun is to the left, but is almost critical to finishing the level. Take this teleporter to the slime area below and hit a switch to the southeast, allowing access to the nearby stairs. A nearby lift will have been revealed to return to the starting area, with the teleporter in the center lowered. This switch will allow you to leave the arena, but more monsters will be resurrected in these other rooms.
Take the lift nearby and pick up the armor bonus, which will gain access to the first fight of the map, relying on resurrected enemies and heavy use of rockets.Ī switch to the east of the arena has lowered and will reveal another switch guarded by arch-viles. Ahead of these is a room with a megasphere, guarded by crushers. Find another switch in here, which will lower some weapons and a backpack. Press the switch just downstairs, then drop into the room and head south. This will lower a path to the west that leads to stairs. Head to the right and stand on top of the yellow platforms. Press the switch just ahead to lower the bars. Sector numbers in boldface are secrets which count toward the end-of-level tally. Letters in italics refer to marked spots on the map.