I'm actually excited about this project a lot. There are ideas in here that I've concepted for a game, but I don't have the skill to do it. If there's anything I can help with, I'd love to. (:
A suggestion would be this:
Try something like CV3 or RoB and give multiple stage paths, so you don't play every stage in one playthrough. That would increase the replay value. (:
Course, I realize it's hard to do, but its a suggestion.