Cool concept. It's obviously a very niche game, but it's challenging for those of us who have rusty music theory knowledge. I wanted to play it but my brain was not okay with that :P maybe a way to trick the brain into liking this would be to add a timer of sorts? (The score thing didn't really work for me)
Visually, while the dark green background instantly reminds me of solitaire, it wasn't obvious the cards were stacked sideways in the center area. Maybe giving them a border and making them actually stack? Oh and I will not forgive you for the use of comic sans :(
The game also needed a "reset" button always within reach. How did you test your game without one anyway? :o Did you assign it to a keybind?
Overall an interesting concept! And thanks for providing us an exe (I know it's a bit harder with pygame)
I hope you enjoyed the jam, and I'll see you in the next one!