Thanks a lot! As you know I enjoyed your entry a lot too! The short music is not due to the size limitation (the game is only 5kb), I just lacked time to do something longer. As a comparison, one of my latest js13k entries contains 165 puzzles and 10 long musics extracted from classical MIDI files, so the size is not a problem if we use the right tools :)
That game is here: https://js13kgames.com/entries/lossst-a-snake-in-space