I agree with
; I think a lot of the blocky shapes could stand to be smoothed out more, especially in the hands. Looking at the feet in the pose in the bottom right corner, they don't look anywhere near as smoothed out as in the turnaround you have up above.
The other thing that bothers me is the mouth in the facial expression in the bottom left corner; something about his mouth when it's open here really bothers me, and I think it's either how it's positioned or the corners of his mouth not being smoothed out very much at all. Even just having a curve showing the skin being pushed over his eyes a little could help with fixing that. It might also be one of those things that could be fixed with coloring.
Honestly though, it's a great design so far! It does have a Sonic feel to it, but I can definitely tell you're trying to stay away from that and being moderately successful at it. Can't wait to see more!