What do siege engines/catapults do?
When you attack another town with a catapult, it randomly selects a building and damages it, reducing the level of the building by 1. Not all types of building can be targeted and damaged. If not all buildings are built in a town, or there are buildings that are level 1, then their is a chance that the catapult will miss. If all buildings are built in a town, then the catapult will always hit. Only 1 catapult can be sent out to war at a time. If a building is damaged during an attack, the information will be displayed in the battle report. Catapults are intended as a high cost item, because of the damage they do to towns. They are also easily destroyed by troops in both attack and defense and affect morale in the same way as regular troops. All of this is designed to ensure that catapult use does not become out of control. We will also be tweaking the system, as we learn more about their impact on the game.