Alright, played the demo again. It's boring. And slow. There is no second jump button, but it does have a sprint button, which you can just tap to go faster. The demo features the same levels they've demoed forever: Seaside Beach, Seaside Race, and Worm Tunnel.
Seaside Beach is the licensed WayForwardvania level. You can run through it pretty quickly as Sonic. If you actually feel like switching characters or spending more time on the stage, you can take a divergent path to grab some collectibles. They're not very hard to find or get to, which isn't bad, but they don't feel very rewarding. I think in the full game you get concept art or Tails gadgets or something.
Seaside Race is the Sonic Rivals level against Sticks. There are shortcuts you can take by using Sonic's air dash or generally following the rings. Seems like you have to mess up pretty bad to actually lose the race, but if you just keep moving you'll be fine.
Worm Tunnel is pretty simple. You switch lanes to avoid the electrical... things, and use Enerbeam to get on a zipline when
the game tells you to press A the worm comes to fuck up the road. Follow the rings to the end and you're done.
Not too engaging, not too surprising. It's a handheld version of a game for a TV show, and it feels like it. But hey, it's for the kids, amirite
edit: addendum
It's the wack handheld version of a new Crash game I've been missing for 5 years
No but seriously, it's really boring. All three levels are basic and bland. Stuff appears to happen and it all basically amounts to nothing. Exploring and grabbing the collectibles doesn't feel rewarding, it's just more stuff to do in a game I don't want to keep playing. It's not actively terrible or anything, but it's definitely not engaging enough to hold my interest.