Common Infected

Common Infected, also known as The Horde or Multi-Racial Gang are the most commonly-faced enemy and the easiest to defeat. They are completely AI-controlled and fairly weak. Their strength lies in the fact they attack in groups sometimes as large as several dozen, known as hordes. While they seem capable of ignoring pain, they can still be killed as easily as a normal human can. They are capable of climbing ladders and scaling objects.

Common Infected react violently to the pipe bomb and will ignore Survivors to investigate it instead.



Appearances and Action
Common Infected come in variety of appearances, both male and female. They are the victims of the vicious virus only known as The Infection that is sweeping through the area. Common infected do not differ in appearance from a healthy human as much as special infected do. Some infected models can be seen in any scenario of the game, while others, such as the infected patients in Mercy Hospital or airport custom officers in Dead Air are only encountered at certain areas. When not attacking, they are very vulnerable when sitting down, leaning on walls, or simply standing. They are easily provoked by light, sound, or touch, but are normally only dangerous in large groups or when completely surrounding a player. The heads, arms and legs can all be shot off, this happening easiest using a shotgun or hunting rifle. The Infected react naturally to gunfire in their vicinity, turning towards the sound to attack the shooter. Shooting one in the foot will cause a very different reaction than shooting one in the chest with a pump shotgun. They are often seen engaging in bizarre activities (e.g. vomiting, attacking inanimate objects, fighting each other) when unaware of the Survivors, but begin to rush at you when they spot you. A common infected's attack slows down the target player, meaning that it's hard to run away from a mob of them that is close to you.

Tactics
Common Infected are only strong in numbers. Sticking together is key to keeping them off of you and your teammates' backs. If you are concerned about conserving ammunition, consider using the pistol, which kills them in just a few shots or one headshot on any difficulty.

When a horde is about to attack, the best tactic is to back into a corner (preferably) or a wall. Assign the front two Survivors to crouch and melee continuously while the two Survivors behind them stand and fire their weapons at them. This works equally well when slimed by the Boomer.

Pick off lone infected whenever possible. When entering a new area, swap to pistols and take out as many lone infected as you can from the entryway as long as it stays quiet. The Director has a tenancy to spawn hordes once you reach the mid-point of areas, and this "event" will cause most (sometimes all) idle infected in the area to attack as well. In versus, however, it is unlikely the boss infected will allow you to sit in one place long enough to clear a room in this manner, so keep moving.

No matter how indignantly the Infected react to Survivors, they hate pipe bombs even more. For whatever reason, they would rather play IED soccer than chase down Survivors, making the pipe bomb the easiest way to clear a room. Even if the pipe bomb did not explode at all, it would still be one of the most helpful objects in the game for dealing with the Horde; it can divert an entire onrushing swarm, or draw every idle Infected out of hiding in rooms too complicated to clear safely. Extremely useful for any situation in which the Horde is "interfering," i.e. fighting a Tank, or attempting to revive a downed teammate.

As cunning as they seem to be (for zombies), the Infected cannot seem to comprehend doorknobs, and it is astonishing how helpful the simple act of slamming a door can be (which would explain why AI-controlled Survivors like to do it so much). Unable to open it themselves, common (and indeed all) Infected must break a door down first, causing a telltale banging, then gaping, obvious and defensible holes in the door in question.

It bears mentioning that "Common Infected" and "Hordes" behave differently and must be engaged as such. While "common" zombies are content to fall all over themselves at random until they spot a Survivor, "hordes" always posses an omniscient awareness of the Survivors and where to find them. Some common zombies will even carry on in ignorance as wave after wave of Horde zombies pass them by. So while common Infected will often permit themselves to be passed by, horde zombies never do, taking any way they must to reach the Survivors, and attacking until annihilated. Statistically speaking, however, they are indeed all the same, and any zombie, common or horde, will immediately drop whatever they are doing to chase a pipe bomb.