A modern, cross-platform Quake game engine based on FitzQuake.
A cross-platform port of Hexen II game.
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Game engine supporting many 3D/2D formats and graphic effects
General Purpose Engine for Graphic Adventures.
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Your death sentence awaits...
Graphics generator for pie diagram matrix from spreadsheets