MAP13: Dark Citadel (Doom 64)

Easily one of the most eerie levels in the game in regard to the demonic architecture and creepy ambience. Not the toughest level, but one that can make you jump more so than others. You will find yourself getting randomly ambushed by Pinkies, Hell Knights, and Barons throughout the level.

There are plenty of Shell boxes and Boxes of bullets, so do not hesitate to make use of them. Be prepared though, as there are lots of enemies in various locations.