Spring is a free, open source, fully 3D, real-time strategy game engine. Originally designed to run content from Total Annihilation. Since it's early days, the engine has matured significantly. While retaining some support for units in TA formats, games for the Spring Engine can now be developed using more modern technologies. Using the Lua scripting language to allow everything from extending the GUI and Gameplay to Unit Animation, allowing units to be created in modern 3D model formats and an extensible AI framework all while having an open licencing model (GNU GPL), the Spring Engine is an excellent choice for any RTS Game Developer. Many different projects covering a wide range of popular RTS genres and diverse themes have already been built for the Spring Engine establishing it as a key contributor to the future success of open source gaming and free to play games.
"Spring isn't just one game but many" - First TA:Spring trailer
The quote referred to Non-Total Annihilation games made on the Spring Engine. But these are minigames made with the Spring secondary scripting language - LUA. Showing how the game can be changed without modifying the source of the engine.
Pacman was created by "zwzsg"
Snake & Tetris was created by "aegis"
(users from Spring Forum)