Instead of building towers and defending against hordes of monsters, play the opposite as an evil mage that builds his army from the ground up to dominate the lands.
Build structures, train army, destroy enemy castles. Your soldiers will charge and break through enemy defense lines automatically and use magic to assist your corps assaults.
The world oil supply is low and the battle for resources is about to begin. A new oil rich desert has been discovered, and it is your duty to claim it for your country.
