Okay, I'm going to be honest, I did NOT like this demo at all. One major flaw is that it's very hard to get up to speed to time warp. Every time I get close, I run into a wall or a spring or something. You might say, "Well I can do it just fine." But that's cause you made the game and you know the right path to take.
Another problem is that it's almost impossible to recollect rings after being hit. Sonic should be able to collect rings after being hit sooner than that. And for the brief time when Sonic is invincible after being hit, his jump is screwed up. He's in his "AHH I'VE BEEN HIT" pose.
Also at the first boss, there's an invisible barrier to the right that screwed me up several times. Please put a solid there so I know when I'm going to stop.
Other than that, it just felt very buggy. I'm sorry but I just didn't get that much enjoyment out of it which is really a shame because it really looked nice. I think with some improved level layout and a second look at the engine, this game could be a lot better.