Hard to understand initially as the "player" isn't very obvious and the window for correct input is so short I still failed when giving it what I hoped was correct input (which then made me think the correct way to play was wrong). A very interesting concept once you get the hang of it and it does feel really rewarding to get a streak of notes in correct timing. Personally I'd like a bit more lenience on mistakes, but if you wanted your game to be for high skill players only then I can appreciate that.