Swing your nail at the buttons to change the song and at the arrows to change the screen. Once a song is playing, you can't change it until it's done. (just click the green flag again) Comment if I accidentally broke or missed something. Also apparently you can play two songs at once so that's a thing.
All my credit goes to DarkLava for the knight and Team Cherry for everything else, from the backgrounds to the music. All the pictures from the game where taken by me. And sorry all the pictures of the bosses where in godhome. I was too lazy to restart the game.