Definately needs sound
The first thing, which I'm sure you know, is it needs sound. Sound will honestly make this SO much better by a long shot. It'll give your animation more impact and the whole deal. So definitely make that your first priority.
Some of the animation movement seemed a TINY bit off, but for your first one and something simple like this it wasn't bad at all, just a tip.
A preloader and some kind of menu would be good, but seeing as this isn't any huge type of movie deal I guess it's fine.
Keep at it though, you'll get better as you go.