Thank you very much for the thoughtful feedback! To address some of the stuff you brought up:
You're right, the sound mixing absolutely has issues.I wanna do a more careful pass on the whole setup in a post jam version.
About the visual feedback, I do agree that there's room for improving things. I think I erred on the side of graphical cohesion rather than contrast and readability. I found your dithering suggestion particularly interesting. My gut feeling would be that the effect would be too noisy, in special on an empty board, but it seems to look alright in your edit, so I will consider giving it a try.
Thanks again for taking the time to write this. Cheers!