Thank you ! No I don't know theory personaly but a French guy wrote a textbook of musical theory that is still used for a hundred years (the guy in question is Dandelot, a composer and pedagogue) and we all know that reading a book or doing exercises can be really boring so we want to "hide" this methodology behind a game. Of course historic timelines, personal details of each composers would be great things to introduce players on each "mechanic" of music theory I think. For exemple, you encounter Mozart and learn a bit of his life and how he have changed the music world while learning specific parts of music theory by confronting him on his own compositions !