*is jealous of your masterpieceful skills* Just amazing. It's perfect, the colours, the style, everything just fits together. 10000000000 out of 10! Plus it's Sonic, and I like Sonic, so that gives you extra marks ^^
Background's a bit simplistic, and there isn't any real flow or depth, but the colors were definitely chosen well and the filter used is pretty good. Also, make that border much thinner.
Thanks :D the filter i used was called line art. I'll read some tuts, since I can't make flow or depth to save my life. I'll fix the border too, that was my first time using one. xD
xD Don't worry, depth and flow are very easy, just read into it, you'll get the hang of it in no time.