While the game for sure is likely best alone, I think a multiplayer would be very fun to just play and mess around with my friends with. It's by no means necessary, but it'd be fun to have. Maybe someone else will figure out how to make a multiplayer mod for the game later on.
I think getting launched through the tree was a bug, but I feel like falling off your ATV whenever you hit the tree could be a new mechanic so players take their time to pass trees and not drive recklessly.
I like the songs, I feel like this could be a demo of a great rhythm game. I think the second song is much harder to win than the first. Besides that, I think it's fun for the time that I played it.