It looks good, especially the green lighting. As for the front of the skull, perhaps you should try adding a little more of the dark undertones in the recesses, and also just a tad bit more white highlights. That said, I'm not sure about adding additional highlights. As Leech said, the front should be shadowed. Perhaps you could work your way back down through a series of shadings.
__________________ 
It's not a choice, it's a Nurgling.
|