Thanks for trying out my game and the advice on the volume controls which will most likely be my immediate improvement on the game.
Regarding the confusion that you had, it is just part of the experience of this puzzle game to let you focus on your listening and intuition more - "I don't know how it works exactly but it sounds nice". I am afraid that the more mechanism you know beforehand it will spoil the game experience more as there is nothing much else in this mini game. To be honest even myself as the creator I don't know how to score the best from it... All I can expose are the algorithms on the random chord generation, scoring system and the music chord corrections which I don't think they will help much in experiencing the game.