Shmup ability ideas?

Score=performance is the most important for me. The better you are doing, the more crazy pomegranate you are capable of doing. Basically, a sort of cascade effect that makes awesome players feel even more awesome and encourages terrible players to get better so they can get that feeling too. Not 1ups, that's boring. I'm talking about the higher and longer you hold a combo without getting hit/running out of time on it, the faster you move/stronger your attacks get, with the negative (for a bad player) being that more and stronger/faster enemies spawn. bonus point if it lowers or even removes cooldown on any dodge skill that may be in place after a certain point is reached; at that point, the screen should be almost filled pixel by pixel with damaging elements, but the potential score multiplier would be equally insane. I've played a few comiket games that implemented that pretty well, but I don't remember the name of the one I played the most...and it was from C72 or something so it's really old and probably not hosted anywhere anymore ;_;.

Oh, and skimming enemies should give bonus points! That makes it so perfectionists like myself are constantly forcing near-misses so they can max their score out!