This is the engine I developed for use in my game, Fedora http://scratch.mit.edu/projects/roosterman3/2535403 I developed this engine to work well on flat surfaces, and it doesnt work with hills very well. it is not the best and there are certainly better ones out there, but i wanted a challenge and i think i did pretty good on it. feel free to use the engine, although be sure to give credit and a link to this project.