Toy Soldiers is a tower defense game set inside miniature battlefields fielded by "living" WWI tin soldiers. The player controls packs of antique armies (German and British) created by the fictional Signal Toy Company of Bothell, WA in an attempt to prevent waves of enemies from raiding their defended toy box. There are 24 single player missions, and a multiplayer versus mode playable locally or online.
In single player, players earn money by destroying charging enemy units (from standard infantry to wheeled guns, and even enormous Tsar tanks). This money is then used to build new defenses on specific build pads, or to upgrade existing ones. As the match progresses, the number and type of enemies increase significantly. The hardest difficulty mode even removes A.I. control of the defenses, and requires the player to switch through and fire every one manually.
Defenses include barbed wire that slows down infantry, machine guns, mortars, artillery, and even poison gas turrets. At any time, the player may control any of these defenses personally, aiming and firing with increased accuracy and judgement as to which charging unit possesses the greatest threat. Certain units also grant new behavior when under player control, such as the ability to manually guide mortar shells. Players can also fly airplanes to engage enemy air forces, or take control of a sniper tower to pick off infantry from afar.
In versus mode, players must still build and maintain defenses to protect their toy box, but must also spend their funds on units to attack their opponent. Players select their next wave of units with the Y button, but cannot directly control their assault like they can with their defense towers.