Zombie

Template:General Zombies are the game's biggest threat, roaming Knox County initially in the hundreds, then even in the thousands later in the game.

Zombie Mechanics

Pathfinding

Responding to claims of zombies 'cheating' to locate players, Project Zomboid developer Chris "lemmy101" Simpson explained the nature of zombie pathfinding:

Zombies can pathfind a total of 20 tiles to reach you. Seems like a lot but any less than that and they fail miserably to ever come upstairs to get you or to navigate around a gap in a fence or something. This all means that if you're at a window and a zombie sees you from outside, it will attempt to pathfind to your current spot, and if it's under 20 tiles travel distance it will work out a route to get you. A bit too intelligent for a zombie perhaps, but until we can balance it such that the threat is still there without this, then it is necessary. If the zombie is over 20 tiles away from you then it will continue to 'wander'.

If a zombie is within a few tiles distance to you, then instead of path finding it will just lunge at you, moving directly toward you irrespective of things in the way.

If you make a sound that's in range of them (and is the relative loudest sound they hear from their position) they will head to a random point within 50% of the range of the sound. So hearing a shotgun blast from 40 tiles away, they will head to a random location within 20x20 around the source of the sound. If another shot occurs when they are 20 away, they will head to a random point in a 10x10 square around the sound.

So if a zombie hears footsteps coming from a few tiles away, they will pinpoint it accurately enough to head to the door to that room.

Zombies will always head toward the sight of flesh, ignoring all sounds if a tasty human (matters not whether NPC or the player) approaches it. But this can be rather helpful, as if you got a spare NPC or an unfortunate NPC comes near your location, you can trick him or her into being a lifesaving distraction for you, whether they want to help you or not.

Movement and Horde Behavior

The zombies in the game are traditional and shamble, but newly-turned zombies move faster. Zombies are attracted to noise, bright light (particularly from a flashlight or fire), and the sight of humans.

Lemmy also provided further information on the behaviour of zombie hordes:

At the start of the game, there are three hordes of massive sizes ranging in the hundreds or dozens at least. About 50% of the total map zombies are put in a horde, the others are randomly distributed around the map as stragglers and loners.

Zombies that not in the horde head toward the nearest horde if there are any in the vicinity, while wandering around outside the player's sight. The hordes all move around the map at a slow speed, heading to a random point on the map, then another, then another.

However, at 30 days in the game, the horde movement will be a little more unrealistic. Instead of moving to random locations, they will deliberately search the map until they find the player, and therefore, makes the hordes much more dangerous.

Combat and Damage

Zombies fight by coming up close to the player and then extends its arms. Damages from zombies can result in three ways: bites, scratches, and "punches". Bites are the rarest, but have a 96% chance to infect you, so you obviously want to be careful so you can avoid getting a festering bite. Scratches are quite frequent, but they only have 25% chance to infect you, but they are still very dangerous even so. "Punches" are just wounds that do not break through skin, and having the thick skinned perk can help you turn the more dangerous bites and scratches into less dangerous "punches". Punches do not have a chance of infection, and when you hover over the status bar of the body part, it will only say "slight damage", without anything underneath. Unlike bites and scratches, "punches" do not require bandaging or first aid of any kind, just some time to heal and some minor pain that can be dealt with by utilizing pain killers.

Zombies are also able to deal "door damage". Although they deal relatively little damage (individually 0.02 or so damage every 2 seconds), they can deal a good amount of damage if left alone for a long time or if in larger groups. Zombies banging on doors will attract other zombies, and it will convince them to bang on doors/windows or just mill around until something happens (if there are already too many zombies banging). Luckily, there is a small chance NPCs and players can dissuade the zombies by staying absolutely silent for a good amount of time, but that can be pretty hard when one needs to walk around the structure.

As of 0.2.0R RC1, there are combat animations that were previously absent in any version older that alpha 0.2.0q.

Infection

Humans (the player and the NPCs) who get too close to zombies may be bitten, scratched, or otherwise injured. Bites have a 96% change of infection, and scratches have 25%, but both are very dangerous. When a character is infected sick moodle appears to verify it, and the moodle's intensity will slowly increase, until the character has a full blown fever. However, the sick moodle can also happen because the character ate raw or rotten foods or out of the blue. When this happens, there will be no zombification, and the moodle will usually go away by itself with rest and by being well fed, and won't be of much harm to the character except decreased abilities for a small amount of time.