Excellent idea and incredible execution! I love the "painting" mechanic and that each color has it's own uses, that you yourself can decide. The fact that you give the player all of this control and yet still manage to make the game challenging is quite impressive, well done!
I don't even have too much feedback to give, apart from a few UX issues with not being able to deselect an action, but that's very minor.
Oh and, the choice of music and audio was superb. Fantastic work!