multiplayer-oriented maps for Doom

 Freedoom is a project to create a complete Doom II-compatible IWAD file
 which is Free Software.
 .
 FreeDM is a sub-project to create a set of levels designed for deathmatch
 play.
 .
 FreeDM does not require Freedoom to play and can be used in conjunction
 with a boom-engine. Please note that this is designed for multiplayer and
 will not be of much use for single player.