Claustrophobia 1024 is the community-made, inspirational sequel to Congestion 1024 which was released back in 2005. It's comprised of 32 brand-new maps restricting the player's movements to a 1024x1024 space. Decoration and monsters were allowed outside of this 1024 squared area. The player is allowed outside of the 1024 boundary given he is killed instantly. The focus of the project was to create a set of fun, quick & good looking maps while being able to work within the boundaries that were set. All of the maps were made to be played pistol start but it also plays just as well map-by-map.
Exiting MAP33 in Boom, MBF, or WinMBF will cause the game to crash. This may also happen in other, similar ports. You can still play the map but you will not be able to see your stats upon exiting. Play the map in a newer sourceport if you want to see your stats (PrBoom+, ZDoom, etc).