One of those 'gimmick' maps in D2, alongside Barrels 'O Fun and (yes) The Chasm, this is one where Lord Petersen decided to not worry about creating anything realistic or related to the storyline of Doomguy going through actual places on Earth and really explore the capabilities of the the Doom engine and level design. It feels like a secret map and personally, I think it should've been, instead of the Wolf3d tribute maps (weirdly enough, the rooms at the very north of the map are very similar to the 'non Wolf3d' secret room in map 31 - why did he do that??). The only thing truly missing from this level is some kind of crusher trap. Love how the the only glimpse of the sky is in the central 'hub' room (which gets highlighted when you pick up the invuln sphere). Watching a cyberdemon get clawed to death by a horde of barons is quite possibly one of the most awesome moments in the game. Love this map