Open-source engine for Heroes of Might and Magic III
Multi Theft Auto is a game engine
fheroes2 is a recreation of Heroes of Might and Magic II game engine
Real Time Strategy game engine supporting early Westwood classics
Open source clone of the Age of Empires II engine
The ioquake3 community effort to continue supporting/developing id's
Voxel game-creation platform with easy modding and game creation
dhewm 3 main repository
Descent 3 by Outrage Entertainment
RPG Maker 2000/2003 and EasyRPG games interpreter
Recreation of the classic Grand Theft Auto III game executable
3D Procedural Game Engine Using OpenGL
An OpenGL RTS game engine written in C
A modern, cross-platform Quake game engine based on FitzQuake.
GemRB is a portable open-source implementation of the Infinity Engine
Game engine supporting many 3D/2D formats and graphic effects
An isometric arcade-style game of skill, puzzles and exploration
SDL based generic 2D game engine
A cell-based puzzle game featuring classic and completely new puzzles
ZDoom 2.8.1 fork focusing on modernisation, performance and stability
PyCAPGE - Python Classic Adventure Point and Click Game Engine
RTSish Game Engine
C++ lightweight cross-platform game engine