- The target reticule is controlled by the mouse; you fire towards the location in which the mouse is currently positioned. Player movement is controlled by WASD in top-down fashion; W is up, A is left, D is right and S is down. The left mouse button fires the current gun, and the space bar reloads. The numeric buttons 1-3 change to the respective gun, if it has been purchased; 1 for the pistol, 2 for the machine gun and 3 for the rifle.nnThe aim is to survive as long as possible by shooting the zombies and not letting them touch the player. The green bar at the top dictates what percentage of the total amount of zombies have been killed. When it is full, the round is over, and the post-game screen is displayed. At this screen several stats are displayed, and the shop can be accessed through the dollar sign button.