Orx is an open source, portable, lightweight, plugin-based, data-driven and extremely easy to use 2D-oriented game engine. It has been created to allow fast creation of games and prototypes. All objects and cameras are created in a 3D space, but only a 2D rendering plugin is currently available (however hooks are provided for those who need to roll out their own 3D rendering).
Feathery Tale is from MateGames written using the Orx Portable Game Engine.