G2
A generic 2D engine for any kind of game
This game engine uses the power of C++, OpenGL, and OpenAL to provide highly-portable, object-oriented code for programming a video game. Rather than tailoring to a specific type of game, the engine focuses on the fundamental components. It covers audio, graphics, controls, and data flow. With G2, developers have everything they need to create a 2D game without the need of expensive SDKs.