Thanks for checking out the new tracks! :) I am indeed the composer as well, I've done literally every job for this game thus far (which is why it takes a while to add new content haha).
I plan to make the game a commercial release once fully finished, and I plan to price it at $15 or a price near that. However the final demo will be distributed for free and will be around twice as long as the current build give or take. Hope that answers everything!