The thing is, I find those rules to be confusing when explained verbally. It makes more sense in game than it does with words. That's why the ideal player experience I tried to reach is playing the game without reading its rules, experimenting, and figuring it out step by step. It might requires some trial and error, but that's part of the puzzle! Seeing a ball lighnting up and a bar filling up is in my opinion clearer than having those concepts explained. That's why I really want to avoid describing rules inside this game: I feel it adds confusion and makes the player believe in a complexity that doesn't exist.
However, there are indeed two aspects of the rules that I believe could be communicated more clearly: it is not necessary to hit every notes (as it is best to focus on one color and ignore inactive notes when we're juggling with too many), and more active notes makes the bar fills faster. I still am not sure how to encourage the player to play this way through visuals and auditive feed-backs. For the first one, maybe I could add an effect on an "active" bar, or somehow emphasis active notes that are "part of the current combo"... But for the second one, it's trickier. Having an effect on the bar that intensify maybe, or displaying a number somewhere (like it's the case once the bar is filled)... Again, the difficulty is that too much information brings confusion!
Anyway, thank you for your feedback! I'm glad that you enjoyed the game.