The demo was really fun. He's right it feels like a Mart Kart-type racer... Except that the cars feel like they have actual weight. Like, you're not just sliding around all over the place.
Only thing I have against this is that when you play as Sonic the Hedgehog, you can get the 7 Chaos Emerald power up, and turn Super Sonic.
On my first playthrough, I was so terrible that I was about to be lapped almost. Then I got two Chaos Emerald power ups back-2-back, and was inches from placing first. When in Super Sonic boost mode, you can literally zoom through half the course, blazing by the competition.
It would be interesting to see what other characters get, however it does seem pretty cheap all the same!
My favourite cart racer is Chocobo Racing on PSX. It looked like shit and was basically an advert for FF8 and Chocobo Dungeon 2, but the magic system and abilities were so balanced it remains a game I will play with friends.
Chocobo in this game could dash, and Squall could use a dash-like ability that cut through the competition until you're in first place. They were not nearly as powerful as Super Sonic in this game, and still managed to give that awesome speedy edge. Why did Super Sonic have to be so annoying to me.

I really want to ride a motorcycle as Ryo Hazuki. Plus, Sega All-Stars Tennis was an amazing game, so I expect the same here!