There's something off in this sheet, and I think it's his colors. His shoes that are inward, the darker one that's on most poses, is too dark and contrasts too much with the other shoe. Speaking of the shoes, the light blue is a bit too light. The spikes are pointed straight too much and they don't look natural, and when they switch from being very pointy to limp, it looks odd.(Example: Air attack) Other than that, the ice ball effect needs work. meh, don't think it's as good as the wind sonic sheet.
Firstly, the colours are not mine, they are from a picture made by super-sawnyc128. All my element sheets are from that picture as well. I have made credit in the description if you havent realised yet.