Like the civilizations, the campaigns are historically based. Lead either William Wallace or Joan of Arc against the Britons, or fight for conquest with Saladin. The in-game map editor also opens up the possibility of players designing campaigns. There are several gameplay modes, the most fun being regicide - where you try to kill your opponent's king before he kills yours. In a solitaire game against one or several computer opponents, the computer will behave human-like, engaging you in commerce and diplomacy.
Kings boasts several other minor improvements over Empires that add up fast.
Buildings are full size relative to units, and units obstructed by buildings or vegetation are clearly visible. You can scroll through idle military or worker units using hotkeys. When an event occurs, such as an attack or the completion of a building, the game notifies you instantly. When a village is under attack, the resource gatherers can be garrisoned inside of buildings for protection, and ranged units can be garrisoned inside castles and towers to pelt the invaders from a safe location. The music is masterfully orchestrated.