I think that Chapter 2's boss level is too unfair because there isn't any way to tell which note it will go to and there is almost no reaction time on most of the changes.

The only way to beat that is to just press every single key at the same time and then you'll get the right one, but then there's the problem that you have no reaction time to hit the next note, you seriously can't win here without missing multiple times unless you are a god which is unlikely, as the game is so short at this current time that you are most likely a noob throughout the whole thing unless you keep trying to get perfect scores before moving on. If you add more chapters, please have this level be replaced with something else and only have it at the end when the game is very long so that anyone who gets there is likely skilled enough to handle it.