Initial speed depend on how long player charge hurt other hedgehog with harder and longer spine on its route.
Rolling hedgehogs isn't a new idea.
HTML = How To Meet the Ladies
Here is my Unofficial Manual for HW. Hope you like it. Still working on it. Don't worry. Will get it finished...Sometime in the future.
This would be one of the top things I'd like to see in 0.9.13 (there's already enough new things in 0.9.12).