I can pretty much agree on with with point.
Animated characters / particles or a proper floor to play on would really benefit the game.
And the rhythm not lining up the enemies is a tricky one. I just couldn't figure out how to properly "sync" the enemy movement to the player one (meaning it would completely brake if the player missed the beat). I went with the "cheap" way and just included a timeframe on which inputs after the "beat" are still accepted. But exactly this offsets the enemy movement with the music itself - sadly ruining a big part of the rhythm stuff.
Oh, have you even tried to use the Level-Editor :P ?
It's a tool that "can" work - but it's missing instructions and due to the limited time you can't even load creations you made (meaning you'd have to replace the original levels for that one) - which makes it useless without the source-code :(
Thanks for your feedback :)