Knuckles -lineartcolor-

This is possibly one of the best artwork of knuckles ever, though the reason for originality being only so good is due to background, though a lot of people do love background, but I definitely, also, the shoes, I really don't know if you were trying to go for a totally different style, or if you were at least trying to make it as highly original as possible, because we both know that sonic character shoes are quite big, even bigger than that.
Everything else though, pretty good, even the tail, that from which is KINDA long, but it actually works perfectly for the back view.