hmmm... yum... nice motion.
dunno if you meant to or not... but personally I'd slide the left foot/leg (ours) forward instead of the right (ours) back... or in other words, he should push from the trailing leg into the whirlwind punching motion...
another nice touch would be to perhaps just have an eye peeking through the hair on the whirling sequence... you should be able to do it if you rais an eybrow and have a bit of white and the red pupil showing... (under the fringe) but only one eye though... whilst I'm on the subject of this element, his ear is missing... I think you need to bring it back here, either poking through the hair a bit, or fully exposed.
I dunno if this would be off style but I think a skull or other logo on the Tee shirt would be an excellent design choice too... (it would add an extra level of complexity to your anims though so think carefully before you do it)
One final point, now I'm really looking at it... I think you need to have the black finger nails appearing as part of the mo-blur of the windmill too...
All in all...Nice.