Nice game :) I managed to get a 20 on some pink, but it seemed like the slider was slightly out of sync with the color channel, and I think the 2nd/3rd iterations should encompass a range closer to the initially selected value, or slow down around it - instead it seems they're just faster, so if your first guess was good, there's no way to just keep it...
Otherwise I like the artstyle, animations and everything fit pretty well together