That's coming along pretty nicely, Indigo. A few concerns..
I can't help but feel that you're over-rendering and individualizing the body parts. For example, that line dividing the chest and the torso. Or the biceps connecting into the forearms. Overall the model and parts read like that of a child's action figure.
He seems to be posed in a relatively aggressive manner with his back arched and arms held wide open, but it was not immediately evident and I had to interpret it that way when I was trying to make sense of his stance. I'm not sure if it's easy or hard to adjust poses like that, but if it is, I'd suggest making his pose part of his character. I do realize that the pose may have a lot to do with ease of construction, so if it does you can ignore this. But I do think you could do more with the character in general.
The last thing I'll bring up is his palms. The shapes you can see hardly reflect that of actual anatomy. The skin beneath his fingers wouldn't wrinkle up like that unless his fist was closed. The base of the thumb and the edge of his hand create this shape that is more reminiscent of a butt than a palm. When both actually gradate on the inward position, creating an inverted triangle that lines the fingers.
While these aren't the only issues, they were a few that I thought were worth bringing up. In the end, I think that you are rendering this model too much, and are only using the concept of skin where it is convenient. There are just too many peaks, valleys, and sharp edges at the moment.
Even though this might read as hyper-critical, I would like to affirm that I do like where this is going. And I feel that you are doing a bang-up job of picking up Zbrush.