Just in the beginning stages,
teeth are too small
Looks good though the scull seems a little narrow from this angle. Also the lack of teeth at this early stage makes it look kind of like its smiling. Obviously when the teeth come in this will change. Generally it is very difficult to make a menacing facial expression when the face has no eyelids and eyebrows to covey anger or menace. I have come across this difficulty many times while drawing monsters and it takes a lot of fine tuning to the muscles of the face to pin down the right expression. I only say this because the face is the thing that most people notice first when looking at model (or drawing). Otherwise the sculpting looks good and faithful to the original.