Nice, I like the detail you put into it. I've seen lots of heads where there's no detail in it.

Currently, no. You are using way too soft shading with it. Use harder brush. Nano-suit's "helmet" has sharp edges rather than smooth curves.

And at first I'd recommend you to do a line-art over the sketch before coloring and/or shading. It really clears it up A LOT.
I'd like to see the mapping in game or on a sphere.
You have basically sketched the basic idea of a crysis head. good job with that but it still needs to be improved.