You could vary the colors a bit and not just have monochromatic gradients for shading to make it a bit more interesting to look at.
The chestpiece looks a bit oddly shaped. More inflated than it probably should be.
Maybe you could flatten it and give it a bit more definition.
The screen I'm on is quite borked in the contrast department so thake this with a grain of salt but it seems there's too much of a jump in contrast between the white and the lightest gray.
Maybe you can brighten everything up a little so the palette has a bit more of an even shading tone distribution.
Hope that helps.
