KeeperRL is an 8-bit dungeon management game where the player is an evil wizard bent on destroying the world and luring unsuspecting heroes into dangerous dungeons.
It’s available on Steam in Early Access, and in something you don’t see very often with Steam games, the entire game is GPLed and the code available from its Github repository.
This is basically being developed by a single developer, and has been in Early Access/Alpha state since 2015, but is updated regularly.
