I don't know what it his, but something about the player feels... strange... maybe is the physics, maybe the controls, mabe both... i don't know... The game is fun, but is heavly dragged down by this problem...
I would also add the ability to the player to "skip the waiting", whitout having to acess it trough a debug button... Waiting sucks in general, and the're only a few games that do it right...
Overall the game is quite good... 4/5, Good Job!!!