I really think Planetary Piano could use a bit more love in the way it works. Only having one note playing when you press a key can sound a bit bland after a while. It would be nice to hear a whole chord of notes, so it sounds more like you’re playing the piano rather than just pecking at individual notes. Also adding more songs would be nice, like having different songs for different times of the year!
I’ve seen this already suggested, but turning down the volume of the rest of the arcade or at the very least other Planetary Piano machines would help with concentration.