Stephen,
You have an exciting presentation here. I like the concept alot.
You asked for input, so I feel comfortable offering it.
Now mind you, I've never painted a flat in my life so I'm only going off of what I see here.
I think you used some very good color choices, and I see you did the standard shadowing on the bottom side of creases and wrinkles, etc. which works well. The only thing is it still seems a little flat to me.
I think what would help is if you also did a graduating drop off on the sides of the face where the colors deepened/ darkened as you went from the nose outward. I'm just guessing, but this might give it a more dimensional look.
I hope you don't mind, I took the liberty of bringing your image in Photoshop to better illustrate what I mean. If you want me to remove the picture, just let me know and I'll delete it.
Either way, what you already have here is very pleasing and a good result.
Thanks for showing it to us.
John
