Pretty nice piece.  I just love the lighting you've got going on here; very creepy.  It's really hard to tell what his hands are doing, though.  They kind of look like he's trying to pray  

Sweet, I love the greenish shading.
The only thing that bugs me is the smoke coming out of his pipes, It looks kind of heavy and not very smoky, but maybe that's just your style and way of pixelling. I would suggest using more colors so that it's more stringy and floaty.

Its meant to be thin.... 

His robotic arm looks a little thin.