Extremely fun game, the graphics look cool, audio is amazing, and I LOVE the custom song mechanic. It's nothing extremely extraordinary but a really fun way to pass the time. The only gripes I have is that levels 1 and 2 are far too easy and then level 3 is a lot harder, I think there could be a more gradual difficulty curve. I also think the levels look a bit empty because there isn't really a background or anything to look at except the notes. There could maybe also be more mechanics rather than pressing W and S, but that isn't really too much of a problem since the core mechanic can be expanded upon and its a relatively short game, but just something that could spice it up.