The mouth needs to angle slightly downward. Remember, a human face is rarely perfectly symmetrical - it's that subtle dissymmetry (is that a word?) that lends our art a sense of realism.
I would personally ditch the hair, work with him bald. The hair's just going to get in the way, although it looks like you just slapped it on for a sense of proportion.
The cheekbones need to be more defined, and the eyes need to be extruded (brought out, not so sunken). Notice how the sword hilt arches there? So does his forehead/eyebrows.
I'll also second the wideness - his hair gives his face the impression of being wider in the movie picture, but it's actually deceptive. So sculpting the perceived wide face results in a skewed sense of proportion.
However, it's an excellent start. Much better than anything I've tried to do at this point. :lol
Try photoshopping the real picture over the sculpture with varying levels of opacity, you'll see pretty quickly where things need to change. More reference is good.