It could really use work. The anatomy is all wonky. The ear placement makes no sense, the head has a really odd shape, and I'm pretty sure arms aren't supposed to look that that, but then again, this should be expected from typical Sonic style. In the meantime, it's nothing too interesting, and his shoes are a bit of an eyesore. Not really much I can say. You ever consider drawing things other than Sonic? Maybe it could help to practice drawing and observing structures that actually make sense.
PS. shading needs to be studied better too.