Meant it as a joke because of how hard it is to distinguish the colours and symbols by the end. I'm completely aware this is intentional, though.
I did like how there was a smooth difficulty curve in terms of the colours, and later on the symbols, getting only gradually harder to see, instead of big leaps, but I'm curious as to how you could make a full game. Do you intend to do variants of sudoku or something similar? Because I worry that eventually it's just going to feel like sudoku with a new coat of paint to those who can see well, and it's going to feel impossible to those who can't. If there's mechanics to do with the colours themselves, that could fix a lot of issues that might arise.