Good points: His hair is bloody beautifully done, the strands look extremely realistic. His nose and clothes are also great - kudos for patience to do the individual zip pieces xD The light shading is also subtle and effective
Improvements IMO: I think his lips curl up too much - even though I believe this scene is a sort of "menacing smile" thing, I think a flatter line would have done this better. The only other thing was his right eye, his eyelid I think should have sloped down more towards the outside edge.
Something else about his eye looks off, but that may just be because I normally shade the pupils in x)
Thank you for the comment! Anyway... usually I try to put in the drawing something on my own, I like to personalize, not to copy from the image completely ... but, thank you very much for the advices, I will keep them in mind!