Press the arrow keys to move the snake around. Try to eat all of the apples without running into the walls or your tail. If you do, you can press the space bar to restart.
The music is from the enemy battle themes in each of the first four chapters of Escape from Ever After, plus the "normal" one heard in the dungeons of Tinder's Castle, the Stairs of Success, and basically all of Chapter 5 (minus the battles against the last two bosses who I will leave nameless to avoid spoilers).