A dead simple 2D game library for Go
Game engine supporting many 3D/2D formats and graphic effects
2D Game Engine
Nintendo 64 Emulation for the XBOX
Paintown is a 2d fighting game engine.
MicroLua brings Lua on the Nintendo DS for easy programming
ssbb/lol fighting game
2D top down arcade shooter
Very Powerfull Crossplatform Qt Based Music Note Editor[Still Planing]
Moddable 2D Fighter for Sega Dreamcast
3D Engine technology with partial tools developing kit.