Let me just start with one statement: This is not as good as any of the Megadrive Sonic games, nor is it even on par with Sonic Rush.
However, it isn’t bad. Strangely, it is both alarmingly fast (during actual levels) and painfully slow (the “adventure” chatty story bits) with some mid-speed boating inbetween. Yes, boating.
So far, I’ve played the first two “zones”, beaten two bosses (a dinosaur, and a big robot with swing-ball set), and I have all the “Material” (about which Sonic says “I’ve never heard of this ‘Material‘, which just sounds stupid…) needed for my next boat, and Tails says to ask him to make it, but there’s no option to do so. So I’m stuck. Pff.