Fun with different colored balls! See how they behave when you shoot them at other balls.
You have missiles of different colors. Use them for asteroids of the same color. If you shoot the asteroid with the missile of another color it simply changes its trajectory and your missile becomes a new dangerous asteroid. Asteroids can attract some space garbage and grow in size. When asteroid becomes too big or you shoot the big asteroid it is crushed into two fragments that become new asteroids. Do not allow asteroids to approach your space ship and crush it.