the eyes look too far apart, but other than that some very good shading. although where is the light source? there seems to be more than one...

Good lighting and volume. The teeth and cheek bones could use a little bit of a darker outline underneath to define them

It's pretty good but the top of the skull looks too flat to be a modern human. Would also look better with a transparent bg.

What is this a skull of?  It looks like a human pygmy or maybe a baby.

Yes, my mistake. I used the pixeljoint viewer, which occasionally bugs. After checking, I agree with your count.

My sincere apologies.   

May I ask how you count it, because my application tells me there is only 11. You are probably using some image included information, which tells you the wrong number of colors, I've should probably have saved it as indexed colors.

I'm getting a color count of 200 from this...