different from past defenders, this game is the difference between each tower must have a power supply, or can not continue to go on fighting. When the players began to build the tower, each tower will have a power that shows when the power can not be used after the fire. Power supply system must be established, and the cable connected to the turret can charge. Power supply system can be a tower of four directions of energy supply, lower is better and so full of the tower, more advanced power supply system of the tower requires a separate power supply system or higher so be filled. Each turret or a power supply system can be upgraded, when the turret when the player is configured to start the game, you can also pause the game, but with a corresponding length of the pause time points.