His expression is very nice and his shading issue is good too (clothes). But I can see two lightsource lights on the whole picture, one coming from the upper left (visible on the shirt) and from the upper right (visible on the leg and on the money bag). Also, why would one of the bags be darker than the other?
Want to give some dough back to all those amazing pixel artists? Donations provide prize money for contests, help cover hosting costs and support new initiatives.