I think the mouse control is too clunky, and I wouldn't give away the player the full control over rotation... I think. I would just remove it, Q/E is better, more intuitive.
I think I would disable starting the level with a jump - this keeps the character in place, and those ninjas run for their death most of the time:P Yep, this way I didn't notice any difficulty spikes that the other players did
Very nice visuals/music, I dig the style;) And I like the chiptune jingle at the end;) Great work!
Edit: oh, and would make the arrows different color - it was very hard to tell what they mean, and in visualy distinguish them from the button. Though, most of the time button was in such a place that it was obvious what it is...