Very creative way to fight enemies! I'm picturing this as a mechanic in some boss fight where the boss changes between the two colors dynamically and you have to hurl the appropriate colored minion at him to deal damage. Another idea I had is what if when you try to hurl different colored enemies at each other, they don't take damage but they both temporarily become a mixture of the two colors (in this case green), and that could give you the ability to combat green enemies. There is a crazy number of ways to expand on this game, really amazing work!