Wow! What an excellent game!
The mechanic is perfect! Story wasn't original but it works, the music could have been more elaborate and could have worked as more than passwords, but it is pretty good! The art style is brilliant and I feel that it could have been better with more time for expansion.
Just great! Maybe the next game can jump out from the confines of the mythology and expand the functionality of the music, such as playing a triad to pacify/destroy enemy, play a minor to summon enemy and other things as such.