I would've fixed the mouth and nose. What I find annoying is the the width of the nose, it's the right size on the flat, but in-game it gets humongous! Narrow it up and center the mouth (move it a little bit to the left).
In short:
Nose, smaller in width
Mouth, to the left, to the left, Mmmm to the left!
Rest is good, well done ^^