Just finished going through the demo, and it's really friggin' beefy! The action is off-the-rails and the beats go well with it.
To be honest, I was still kind of sloppy on my first run, but despite the times I missed, I still had a blast.
Best of luck making it, and hope you have fun making it as much as I did playing it. I can't wait to see how the full game will turn out when it's finished!