As a suggestions, I think it would be great if you could add a replay view when the player beats a level where it shows all the attempts at once similar to super meat boy.
This video illustrates what I mean in case you are not familiar with super meat boy:
Hey really nice game. Great job. By any chance, would you be interested in sharing/selling the source code? I think it could be a great tool for learning
hi, great game! I am a fellow game developer and I was wondering, do you guys make enough money from the donations? How do you guys manage to find such a talented group of developers and artists to collaborate in a game where there is possibly no economical remuneration?