A simple and easy-to-use library to enjoy videogames programming
Open source HTML5 game framework that offers WebGL and Canvas
Desktop/Android/HTML5/iOS Java game development framework
Examples of procedural geometry for Unity3D C#
The Atomic Game Engine is a multi-platform 2D and 3D engine
Open-source, cross-platform, C++ game engine for creating 2D/3D games
Modern AS3 Game Engine
Egret is a brand new open mobile game and application engine