This is a neat idea, but in my opinion TPT is better without sounds, not to diss the idea or anything though.
Music is something that you can add from your own playlist by playing it in the background, not everyone who plays powdergame will want to hear the default music that will come with it
Maybe if there were a feature where songs could be dropped into a folder in the tpt directory and the game would recognise them
But the thing is that TPT isn't about Sound, it's about particles and how they react with eachother, Anything else can be added externally.
Of course, that is just my opinion :P (Jeez its late, I should be in bed...)