A lot better thatn I could've done... but his face is funky, it looks like he had a warhead or something (war heads the candy, something sour) You should also pull his crotch up like orbit said...
I DO watch naruto (acchually haven't for a while thanks to not enough time and the cop with naruto getting screwed up.) Lemme refrain that, I DID watch naruto, and read the manga, excellent series by the way.
Anywho, the hair on the back of the head goes out to much, it's only very slightly supposed to stick out, if at all, The proportion of his legs to his body, from the side, look wrong, it looks like he's a fat man and pulled his pants way up like fat men do (no offense fat people... but they do! my dad does, and he's generous with his food!) Anyway, pull his stomach out a little, he doesn't starve you know, pull his belt down a teeny bit, and maybe make his stomach flat but curved horizontaly.
Edit: oh yeah, at his torso, his spine doesn't break... it looks like he lost a peicie of his back or something cause it goes in on his back, and make hist tomach flat vertically!