GemRB is a portable open-source implementation of the Infinity Engine
Game/Scene Development System
Game engine supporting many 3D/2D formats and graphic effects
ZDoom 2.8.1 fork focusing on modernisation, performance and stability
RTSish Game Engine
A free 3D game engine to create games and realtimes scenes for Windows
A fork of Chocolate Doom with small Quality of Life enhancements
A fork of dhewm3 with an emphasis on modernisation and vanilla Doom 3
DOOM / Heretic / Hexen source port with enhanced graphics and UI
A cross platform Lua based game engine
scriptable game engine with built-in support for 2D graphics and sound
high performance cross-platform game engine
Paintown is a 2d fighting game engine.
A 2D game engine base on OpenGL and SDL,support for Windows & Linux