Kingdom Rush is a series of tower defense games set in a medieval fantasy setting. In line with the tower defense genre, each level presents a pre-determined path with spaces along the sides called 'Strategy Points', where the player can build towers. Enemies will come along the path in waves and it is the player's job to make sure the enemies are dispatched by towers before they reach the end. By spending the gold earned by defeating enemies you can upgrade towers, making them deal more damage or in the case of the barracks have more health. In each game there are four basic types of towers to strategize with; mage, archers, barracks, and artillery. Different enemies in the game sport resistances to certain types of damage, so which tower you put where is the lynchpin of a good level strategy. At the players disposal are spells that recharge over time. The reinforcements spell summons two brave soldiers to the path to block and deal damage to enemies, the meteor spell (called thunderbolt and soul impact in later games) calls down a rain of fire to blast away enemies.