SDL based generic 2D game engine
Free and Open Game Programming Language for Windows and GNU/Linux
Built to be ease of use, with no programming knowledge, Multi-platform
A runtime-programmable, cross platform, game engine
A generic 2D engine for any kind of game
A retro style video game engine for RPGs and adventure games.
A cross platform 3d c++ game engine
Free MMORPG Engine. Develop and host graphical browser-based games.