In each city you need to destroy the buildings until you find the Roc's egg. There is an egg hidden in most but not all of the cities. You will need to punch the buildings to demolish them, or flame them to set them on fire, while fighting off the other creatures on the screen. Watch out for the hornets that fly across the screen and sting you. Be wary of the weapons the humans try to bring to bear. You will need to destroy these before they destroy you.