Decent game
This game is cool, mainly because of it's simplicity coupled with the smooth gameplay and graphics.
I think however, that the reason why this game is so "hard" and not beaten yet is not the diffculty, but the repeativeness. I did not get frustrated by the hard levels, but bored because I had to constantly start from the beginning, and the first levels are simply a waste of time in the end.
I realise that this repeating gamestyle is probably exactly what you intended, but maybe you might be able to create a game in the future, in which difficulty alone makes it harder to proceed, instead of the constant repetition of early levels. (Hard, if not even impossible to do with the gameplay in this game here, actually)