Some things to keep in mind:
Ease up on the gradients for the character graphics. If the arms are seperate from the torso (which they were) you should make sure that the colors don't end up looking too different. I don't know if you meant to make it that way or not, but it just looked a little weird.
Also, the movements of the arms kind of sucked when he was running.
Other than that, not bad at all. Keep it up.