I like the idea of an achivement award. I know kongregate use such things as well as highscores but as you said before you dont want to use highscores. Thats all good, i think achivement awards are a good idea though, gives people other objectives instead of just rushing to the end. Or you could make that another achivement, collecting them all, finishing in a certain time, and even perfect finish withough dieing.

It probably would require a fair bit of time to get it all working so i guess you got to think is it worth it in the end. Could always take the idea's in for the next game.