First impressions, graphically it looks great for a wiiware game, and I like the music. It seems really 'zoomed in' though, I feel like I can't see much of what's going on around me. Could they not make it zoom out when you start going fast (what game am I thinking of that does that?) By the time I've seen an enemy or a wall I've usually already hit it. The physics is generally OK, but Sonic starts off really fucking slow from a standing start. I guess I've probably played Sonic games 'wrong' since I was a kid, because I've never really gone for the breakneck non-stop haring through the level like a racing game without much of a clue as to what comes next and just hoping that the bumpers etc are in the right places (or that you've remembered enough of the level) to get yourself to the end. I've usually preferred a more methodical and exploratory approach, which is a pain in this ass on this one because everytime you take your finger off right the game grinds to a halt and takes about 3 seconds to get going again.
EDIT: Part of the Casino Street music really sounds like the leekspin song.