Awesome.
I can see what you mean by something is missing, but I'm slightly torn. I agree with what you say, and you could add something to the background, but at the same time, I like the simplistic background, and adding something would ruin that.
The only reason you lose marks is for the hair. I don't like the way it completely covers the face and it goes in a different direction to what you would think. I think that if you were to fix that it may add that little something you're looking for.