Greatly designed! A great puzzle concept, and quite well executed!
My biggest issue is how unintuitive and slightly irritating it is to click and right click each tile one by one, and picking another color after you've finished with one, and how the UI is kinda... there.
But I'm fine with the unintuitiveness - this is a high tier puzzle, which had me broken for some good time! And still has me, with that 4 color level ( ; o;)