Nice idea on a platformer! one of the things that might be nice if you could figure out how to, is to not restart the audio loop until the audio loop has finished. Even if you die. This way it gives you time to enjoy whatever chiptune you wrote for your game. This would also give you more freedom of how long or short you wanted your song loop to be without sounding to odd or off when a player dies.
My only complaint is not being able to use the arrow keys or up ASWD keys for the main menu. I had to click with a mouse haha.
Great job!