There are more and more zombies in the world. In order to prevent zombies from killing humans, as a professional special force, you need to use weapons to protect humans. In the game Zombie Idle Defense Online, your task is to avoid the attacks of zombies and kill all the zombies that are about to arrive. You can repeat each level as many times as you want as you overcome each level you can improve many of your characteristics such as barricade, steroid, healing kit which will help you destroy by the sky, air to all the zombies close to your defense post. Use the mouse or touch the screen to aim and shoot.