EDITED 12/8:
I previously complained about this game not showing what key goes to what color during actual gameplay. That has been fixed, and it makes a huge difference for enjoyment. I still made lots of mistakes before getting a good run, but that's on me this time, trying to anticipate the next color and failing. Results can still end up varying, though, depending on how many times the same color turns up repeatedly.

(to give an idea of how much that change helped, my best score is now 42, up from 37)