Thank you so much for the kind words, it meant a lot to me that you noticed the effort I put into introducing the mechanic :)
I used 2020.17f1 and did some fanciness with custom postprocessed shadergraphs in URP to get the 'color removal' effect. I've heard that URP, 2020 and WebGL don't play well together, but I waited until too long into the jam to realistically downgrade or fix (I tried, but I could tell it was going to be a fruitless time-suck).
Lesson learned: build early and often.