
If you're going for semi realistic, I suggest not to mirror the teeth and veins in the eyes ;)D

It's fucking sick.
But I think the shading is a bit to red.
Try a bit more brownish tint ;)
I hope you made all the shadings on different layers!!
Simple color overlay will do the trick ;D
Hammer could be cool if it's a bit more transparent.
I love the symbols.
This looks great, 512x512 really allows a lot when working with pixel art, a tip on shading though is to try and interlace with a checker board pattern. In 512x512 it would barely be noticeable but it would look much smoother. Also for a bit more evil C&C please remove that symbol on the back, it really doesn't fit in my opinion and you could do something so much better there.