What a lovely warm feeling I got from this when the music kicked in, felt like I was in my old bedroom again back in the 80's! Got 18 coins and the diamond, no bugs found as of yet. Have you thought of employing a different filter over the music for each system too, or different instruments so it's still the same tune, but sounds like a different machine? Best of luck with the rest of development :)
Thank you so much for the kind words! About the music filter, I did considered it, but didn't focus on this so far. There is a slight difference in the sounds pitch on the Pomo D'Or, the black and white TV one, but that's about it for now. Will think more about this after I finish all the content and I get to the polish phase.