In overall is quite good, I like the idea. The helmet, glasses and back part are really well done. The weakest part maybe is the mouth, I don't have any issues with the eye and nose, but the mouth is flat. It is pretty easy to solve the problem, you just have to add the back part of it, the teeth that are behind, and they don't have to be as well done as the front ones, just showing a silloutte would be enough to solve the problem. I know that you could think that as it is on a profile view they are not supposed to be there, but they should, or at least a dark silloutte . In my opinion if you solve that problem you are done.
I am sorry for my English but I am not a native speaker.