I really enjoyed the demo and im looking forward to the release!
I dont quite dig the health system though. If i didnt miss anything it just recharges after a while, right? I think it might be more fun if you had to meet certain conditions to get health back, like jumping over nodes or collecting something/hearts/health on the screen as it often feels like health doesnt matter at all until you really screw up, which means that parts of a song that are more quiet cant really hurt you at all.
Also it could be more clear visually when you have to jump and i hope that there will be some more variety, like different obstacles or powers in the later game.
That being said, i love the gameplay and the general idea. Your art style is great and i adore the atm enemy.
i really enjoyed myself and consider purchasing the full game when it comes out.
I wish you the best of luck and success!