I liked the demo a lot. I played it for like two hours, so I guess that is a good sign!
I had no framerate issues at all, but for anyone who is worried that should be an easy fix, not to mention they can always patch it.
My main problems with the game are that the weapons are stupid at least by design - Just weird generic stuff that has nothing to do with SEGA and the announcer is just not funny or... Anything. I am sad to say I will have him off at all times.
But with this, we can see all of the 24 levels and... Holy shit, what a disaster. Absolutely worst part of the game. Why does Billy have three levels? Why does Amigo have three levels when none of his games let you explore them? Why are there NINE Sonic Heroes levels? I guess they wasted their whole budget on characters... Oh well, at least they look nice, I guess, but they better have some good DLC courses! Three Seven Speedway FTW
The best part of the demo though is the intro. Jacky's special move is so amazing that I think people should buy the game just for that.
And the new SUMO logo is excellent, too bad they could not have done the same with the SEGA logo!