Overall, the style and polish on this feels very, very professional. Excellent job! The boomerangs feel very satisfying to throw, and everything from UI design to hit effects to that sick-as-hell death animation are all really awesome. Feels very much like a game I could play on the app store etc.
The "loop" mechanic of playing through the stage layouts over again is well-done. I will say that I feel the game feels a bit slow for my tastes -- the boomerang charge feels like it takes forever, and you're forced to use it to kill the shield enemies (which I was frustrated that I couldn't hit from behind... felt very counterintuitive).
I really didn't like having to CTRL-ALT-DELETE to close the game due to it being in fullscreen exclusive mode on Windows (unless there was a button I didn't mash that closes it).