Doomsday 2000

Doomsday 2000 is a rogue-like game with a science fiction setting. An alien race called the Zytts have invaded planet Earth. The player is on a mission to recover an anti-matter bomb in a military installation in the Appalachian Mountains.

Levels are randomly generated into 16 different regions per mission, side levels (warrens) and detention levels. The rarity of items is also random making a certain type of item rare in one game but common in another. Aside from weapons the player will find many other items which can be used to interact with the environment. Instead of "magic items" the game has strange devices. To find out what a strange device does the player must identify it at a library or find out through trial and error.

Initially the Mainframe game featured only a single mission, this was later expanded to three.