I think more and darker cast shadows would really help to make this guy pop, especially around the face and hood.
The shape of the head seems a bit odd under the hood, a little too much of a dip before the front edge.
The far hand is pretty well done, but the close hand looks a bit weak.
About the shirt, it's is a bit more wrinkly than I prefer, but that's a personal thing more than an actual problem. Perhaps, however, you should lighten up the bottom of the shirt a bit, it looks a bit odd without any highlights down there, especially considering his posture. Maybe some little strings or a pocket on the hoodie would break up all the wrinkles a bit.