Hue shifted outlines are kinda interesting. Have you done a version with unbroken, single color outlines?
The chin area is a little squarish - like he has a growth on the right side of his neck. I guess its a muscley neck, but shouldn't we some some neck on
his left hand side too?
In fact, the head itself seems blockish - which is okay. But something you might want to look into is that there seems to be two light sources affecting head, but one light source is not affecting the hand, while the hand has another bright light source from below etc. Also, there seems to be perspective for head and body, but not feet.