I really like how you interpreted "musical fruit", it's a very fun way to have a song about music without being a rhythm game :)
I had an issue with controls though, as I'm using an AZERTY keyboard (from France), it seems Q and W are not recorded correctly!
I think what's happening is your engine is recognizing the right key (by position) but your character check makes it wrong, which means I can't play in normal or hard mode! :(