There is background music! How are you playing the game? Try pressing space (the background music stops after finishing a song currently, unless you start it up again).
I went with a specific height jump because it would allow me to go with a certain kind of level design. If I changed that now, all the levels would have to be adjusted. The lack of influence in how high you can jump is part of the difficulty.
I'd love to see a link to your demo once it's up!