When I first played the first POM I didn't like it for the reason it had no goal. This on the other hand gives me a purpose on sitting down and making a song sound good. Excellent game in my opinion, all the haters can sod off.
How interpreted the game was that Pete, the protagonist is in a coma. He ventures through this dream world and gets faint messages from the outside world. Ringing the doorbell in this case probably means somehow the last push to wake Pete up, but there are some parts of Pete's mind that want him to stay in the world and others who want him to return to reality. A lot of people seem to be wondering why there's no clear story, but asking for a story in such a game like this is like asking you to explain abstractness. A wonderful game in my opinion 5/5.