@ Mechanolith: and @ Alistaire: It isn't a gradient, he just blurred the colors to make it look smoother. @ BlackBelt: Try to make pixel by pixel shading without the help of any tool.
I may agree with @ Alistaire about the shading, you shape is amazingly accurate, but your shading clearly shows some gradient-like texture, and this sucks.
I'll like it hoping you fix it on your next skins, good luck.