The folds on the pants look good, however, they seem kinda like the generic folds you see every day. I would have tried mixing the folds in the pants up a bit, for starters, seeing as how the spiral folds(that many use when no actual reference is used, from what I've noticed...) seem to be the same on both legs. I wish I could make more sense of what I'm saying, but at this rate, I'd be writing a book over something so small. Also, I'd suggest thickening the legs a wee bit, as they seem a bit teeny. Also, his arms seem kinda' sloppy, almost a completely different style of shading than the shirt or head. Gives it an incomplete look, especially the fingers
The eyes also seem kinda flat. I would suggest bugging them out a bit, much like the eyes of a chameleon, to give it a more lizard type look. I also agree with the bent horn.
And again, why is there no red lighting on the pants, but it is present on the shirt and arms? Does any one else see this as a little bit strange?