You are Creativity. You live in a musician's mind. You need to escape creative block by finding the sound of 5 instruments spread around the stage [headphones recommended]. Pay attention to the sounds to find all instruments. The nearer you are, the louder it will be from the side the sound is.
The songs are a "rock-ish" arrangements of classical music (the links are for the actual game songs):
The control instructions are in-game. You can play on keyboard or with an Xbox controller.
Some new screenshots: