You need an origin. Once upon a time there was a travelling circus who's ship crashed on an distant unpopulated land. Now, after thousands of years, the entire land is populated with their descendants and their culture has been passed down through the years.
Since the treasure spawn is unlimited, you can just walk back and forth between two rooms and get unlimited treasure farming if you are into that kind of thing.
You might want to put a cap on the spawn.
It would be nice if there was an opportunity to save your song after the level ends, that way if you don't get a gold star, you don't automatically lose your whole song.
When making your "song" look at the number of squares in each note. If you play that note it will put a block there, if you play it twice it will upgrade that block. But, if you play that note again it will disappear and need to be placed again. Since your song repeats, you need to take that into account. Start with the blocks closest to the spawn and play notes outwards to block the stars.
What it sounds like isn't important to the game, just a neat perk.
Nerdook makes some of the consistently best games and is incredibly prolific. Why do people whine so much about his games? There are literally hundreds of inferior games on this site that get far less criticism. Thank you again Nerdook.