Noise

Noise attracts all zombies in a general proximity towards the player's presence. Some actions generate more noise than others, and therefore are more dangerous to perform. There are many actions that make noise that will attract zombies. These include the following:

• Fortifying a door or window with a barricade
• Running
• Walking
• Fire
• Firing a gun
• Chopping down a tree
• Using the "shout" function
• Smashing Windows, Doors and Walls
• Construction
• Knocking down a door
• Setting off a burglar alarm
• Other zombies knocking at a door
• Sneezing and coughing

Noise can be muffled by walls, doors, and distance from the generator of the noise.

Sometimes the metagame will have helicopters fly overhead or random gunshots fired to move hordes of zombies around the map.