Map takeaways:
- There seem to be two triggers near the South switch in the rocket launcher room. If you can skirt the edge, you won't lower the Revenant walls and only have to deal with the Spectres, which grants you an opening to get the jump on the Revenants near the Megaarmor. This room is very dangerous, so this is extremely helpful.
- BFG is located in a room near the yellow switch that is opened when you hit one of the switches in the rocket launcher room, on the half-circle wall when you're at the top of the stairs.
- Getting the invulnerability switch (in the small room where the two pinkies are) is invaluable for confronting the Archvile, as it revives many enemies as it comes out of hiding. The trigger for the Archvile closet is the elevator with the two switches in the shaft, right before the red key, and one of those switches opens the pillar revealing the invuln.
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