Sonic inspired physics in Unity

This year I just wanted to see how far I could get implementing the physics described at in Unity. Two major tools need to be implemented: a tile sheet editor and a tile-based level editor. These tiles need to have particular heightmap data, so other tile tools will not work. The third hurtle is to implement the physics. The fourth task is to integrate these physics and Unity's physics, using these physics for interactions between actors and the world, and unity's physics between actors. Finally a demonstration should be made. I think I can get through some of the steps during GGJ15. I am hoping to learn about how Sonic implements physics and about how custom editors work in Unity.
Jam year: 
MS Windows, Mac OS X, Linux / Unix, Web browser with special plugins or packaged apps
Tools and Technologies: 
Unity (any product)
Technology Notes: 
Still very incomplete. Ground registration is happening sometimes.
Installation Instructions: 

The engine is still very incomplete.  Unity source files are provided.