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.
Defend your base against incoming enemies from all sides. Your commandos have ability to call special orders, upgrade turrets and towers. Playing 'E'ndless level gets your score on the leaderboard.