The art, as other testers pointed out, was awesome! But there is a difficulty spike slightly after we are told that we can double jump. I think restarting and checkpoints could have been better coordinated except if your game was meant to be very hard. Fun and casual until you get stuck and try to speedrun the thing.
[EDIT] The game is not that hard if you understand the mechanic! Maybe a tutorial or a demo of how to use the green paddles would be useful to players.