Crossfire

"Crossfire is a multi-player graphical arcade game ... It has certain flavours from other games, especially Gauntlet and the rogue-like games (NetHack, Moria, Angband, and Ragnarok.) Any number of players can move around in their own window, finding and using items and battling monsters. They can choose to cooperate or compete in the same world." - Frank Tore Johansen, author