I originally started this edit just to add some aa and change certain highlights, but I ended up changing it more than I'd expected, sorry:
just a few things:
- Eyes may be white but they still receive shadows.
- the biggest lighting error I saw was the bottom right part of the (our) left eye cavity area which I think should be lit.
- Antialiasing. On a piece of this size, a pixel is the equivalent size of a small pea (about 4mm); certain parts, like the pupils, may need to be adjusted by less than that distance otherwise they'll look like they are a few mm in the wrong place. (I'm sure you know this, I'm just saying this for others).
- a few anatomy changes
I hope the edit is useful, and sorry if I went overboard.