Everything's a bit choppy and poor quality, it'd probably be better if it were a lot smoother. And I mean, not to bag on you, but it isn't as amazing as it's being made out to be, it's the original picture erased/cut out with some space stocks on lighten/screen/whatever, and shapes. However, it looks like a pretty cool composition overall, so not a big deal to most, I guess.
Oh, and it'd probably be good to get rid of the reflection in his helmet.