Elks edit was pretty instructive. Even if you're going for a cartoony style, his edit is still valid because it defines the volumes much better.
Here's the problems that stick out to me the most. In order.

A. The vertical line here seems to have no real purpose ( same for the other side ). My only guess is it's to define form, but then you highlighted the left side of it for no apparent reason. Judging by the mouth I would expect this to be in a shadow ( since the light source seems to be coming from above ). This is confusing to the viewer.
B. The top of his head is highlighted, but what about those ridges? You would expect them to be highlighted too because they are sticking up.
C. Based on the highlighting, I bet if I did a 3d extrapolation of that pectoral it would be sticking out of his chest 1-2 feet.