first of all i like the concept of the model and you made it quite well.

the only problem i see is the unclean mesh. This will be a hell to animate, unwrap and modify later on.
Also it causes lot of shading problems as you can see. Sure, smoothing groups can handle it a little bit, but this is only hiding the problem not solving it.

with a little more mesh flow (edge loops) it would work a lot better. And on top of that it will help you save a lot of faces.

keep up the good work
and hope to see more soon

cheers