I think what you've got here is a design that really should have been refined a little more before you went into the details phase. In general, your shading, texture, etc are pretty solid, but there are some issues with the basic linework that are keeping it from being as good as it should be.
I think the first thing is general proportions. On the one hand, yes, this is a cyborgyetiman, so accuracy to life isn't perhaps a top priority. But at the same time, things like his lack of forehead, different leg lengths, uncomfortable-looking right arm (our left) can detract from the piece.
Another thing to consider is the silhouette/general composition. The silhouette of a piece says a lot about how you'll view it--if it's recognizable and has a good "flow" to it, the entire piece can be enchanced. As it stands, I think his pose is a little "flyswatted", as Arne puts it (
in his fantastic tutorial). There isn't really a flow to it. You've also put his chest and shoulders in near-profile, but his hips and head in a more 3/4 view. That's tempting because you want to show off all of his cool accessories, but it's pretty much always better to have a good composition--everything looks cooler that way.
Here's a quick silhouedit, with yours on the left, and a potential revision on the right. It's certainly not the only possibility, but it's not that far from what you have already, and it's a relatively popular choice, basically a standard contrapposto (popular with artists as diverse as Donatello and Adarias). The < leg is engaged and bearing most of the weight, leaving the > leg ready for movement, and lending the entire body a bit of a pleasing s-curve. It's rough, but the basics are there.
Anyway, I think you've got a good thing going here, but you could get a lot more out of it with a little more effort.
