RetroArch is a frontend for emulators, game engines and media players.
A MUD client for Android, iOS, Linux, Mac OS X and Windows
3D Engine c++
A promising chess program
Orx: Portable Game Engine
Old style soccer game with many exciting features
God game: wage war from the stone age to the future
Run Windows applications on any computer.
A cross-platform interpreter for many point-and-click adventure games
Remake of the classic Caesar III game
Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
Open Game Bootstrap
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3
Cross platform Game Creation Software
A puzzle game of rules acting upon rules. Create the desired pattern.
Original turn-based strategy wargame & boardgame
Nurikabe, a great game.