Blue alien eats only blue food, Green - green. If it is the other way around: Blue eats green food, and Green eats blue, then minus half of life! If they both miss a meal, and it gets to Yellow - then, too, minus half the life! If you get 300, 500, 1000 points (etc.), then this is plus one life! If you play with the mouse, then make sure that the cursor does not fall on the fields for the touchscreen (two ovals at the top)! This is for playing on mobile devices, and by clicking on the blue oval, both aliens will be triggered, and this will interfere!