Desktop/Android/HTML5/iOS Java game development framework
Free game engine for development of desktop, mobile, and web games
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
3D Game engine with editor
Multi-platform 2D and 3D game engine
Flax Engine, multi-platform 3D game engine
3D Procedural Game Engine Using OpenGL
Doom-based AI research platform for reinforcement learning
A free Chess program for Windows with a large set of features
0 A.D. is a free, open-source, cross-platform real-time strategy game.
3D modeler, 3D game maker, 3D demo maker
Combat Flight Simulator for LINUX. WW2. Network and VOIP. Open-source.
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
3D C++ Game Engine - yet another open source game engine
A 2D game engine and level editor
MAME Android Emulator.
Easy fine console input/output for java
Game backup loader for Wii and vWii
The Atomic Game Engine is a multi-platform 2D and 3D engine
Realtime 3D engine for game development
Bot for id Software's Wolfenstein 3D
A public domain cross platform 3D game
Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
plugin-based RPG manager in C++ and Qt5