Not bad
The art work itself isn't bad, in fact it's very good. The animation was pretty smooth, but the flash itself seemed to look gritty, and seemed like it needed to be cleaned up. Although, I don't know if you were going for that look.
And this is my personal preference, but I think there should have been some sound, either just little sound effects or have the animation set to music, but overall this isn't bad for a first submission, you could have always done ALOT worse.