SonicGLvl is a level editor/formats library for the PC version of Sonic Generations. It's licensed under the terms of the GNU General Public License, version 3 (GPLv3).
Current Development Roadmap: http://i.imgur.com/MiHNVrZ.jpg
All information regarding this repository should be found here: http://forums.sonicretro.org/index.php?showtopic=27333