Its a very creative concept. I think you could make a very cool game out of it.
But i still think the mechanics could be a bit more easily understandable for the players. I.e. the goal of the game, the mechanics behind the enemies and what each colour does. Maybe by indicating what effect you've reccived when on each colour of paint. Giving the player feedback when they reccive points and making it a bit more obvious why they have so.
I'd reccomend letting someone playtest the game. Giving them the game without too much explanation and trying to understand why they might not understand certain parts of it. Taking your time to itterate on the user experience of the game until players can pretty seemlessly understand the mechanics without explicit explanation.
Again its a very cool concept. But try to think about it from the perspective of new players when working on it. Maybe try to find some creative ideas for how to communicate your ideas to the players. And you'll make your ideas shine a lot more