Click the screen to launch your weapon at the undead. Move your finger or mouse to aim at the zombies. Pick up power-ups to enhance your firepower or receive temporary invincibility. Avoid the zombies to prevent them from overrunning you. Endure as long as possible to achieve high points. Battle with friends by matching scores on the leaderboard. Access new weapons and characters by progressing through the game. Look out for special zombies that demand more hits to defeat.