Not too bad
The gameplay is fun, I bet I'd love it on an iPad/Phone. The physics seem a bit rough though. Like, the ninja's jump and trajectory don't quite correspond to the little dotted projection line (which is something that would have been a great optional feature on Angry Birds) and, admittedly, I played up to the tenth level and got frustrated... but other than that you've put together a fun and challenging little time-killer! In short, bad physics can kill a physics game.