A modern, cross-platform Quake game engine based on FitzQuake.
Odamex is a free, cross-platform, modern client-server Doom engine
A cross-platform port of Hexen II game.
3rd Party Video Games Developer: MetalManGames, titles of games
A free 3d game for PC that does not limit the player. Fight,Build,Gain
A real-time 3D Engine written in Ada
DOOM / Heretic / Hexen source port with enhanced graphics and UI
A fun realistic multiplayer free-and-open-source first-person-shooter!
3D-Accelerated open-source DOOM engine
EDGE is an advanced DOOM source port
Three dimensional first-person space deathmatch!