Very good.

This is an awesome piece. I really like the pose, and how it melts into the background on the bottom of the picture. What I didn't like were the veins, they look rather weird. If you're using Photoshop, I suggest you try my technique for this next time: just add a new layer on top of everything and set it to soft light. Start drawing white lines with an airbrush wherever you want the veins to be. You can add black lines later as well. If you aren't sure about how this would look, you could take a look at my Biomechanic Dude's mouth.