Sonic 3 and Sonic Adventures are the best games since Sonic 2.
Since I have just watched Zero Punctuation and now seen that clip, I am going to end up sounding ever so slightly like Yahtzee.
The graphics were incredibly impressive, again showing the well renowned cartoon style of yore but containing a very detailed environment but does at times looks a bit flat. The speed is blistering, but may become incredibly difficult to control, especially during the random button sections.
Unlike Yahtzee, I don't see random button sections as a really bad idea especially not in a game such as this. However, they may require a large amount of practice to get used to the short amount of time each section will give you.
This could be a very good game, but I fear it may be a bit mediocre, as most Sonic games have started to become.