Doing a wild thing and defaulting the new music tracks to "on" for the main build! If you want to go back to original music, you can still toggle it at the main menu with the "]" key.
I'll be adding some more tracks throughout the week, and doing a big full post about this when the whole thing is wrapped up. Although there's a good chance even after that there will be some new tracks added as well, hop in and check out the stuff!