I'm not 100% on the art/polish, but I really like the idea; I think it's good enough to warrant a bit more attention on the design side.
Very cool concept and I can imagine kids and adults alike being able to get something from it. Going to download it now. Best of luck with it!
Update: Downloaded and played it. Definitely needs polish but the basic mechanics are good. With a bit more gamification of the progress through levels, I could see this being an excellent little game for a kid especially.
Red and green making yellow might confuse children though whose mixing experience with paints would have them expect brown?