Left 4 Dead by Steam, is a popular first person shooter surivial game. A brief article about the game and its gameplay can be found here. The following article is specific to the "Special Infected" of Left 4 Dead and how to increase the chances of surviving them.
The Boomer
One rule for the Boomer; keep a long distance. These nasty creatures will vomit bile on any unsuspecting player that gets too close; and this bile not only temporarily blinds players, it attracts the Horde of normal zombies. The Boomer will also explode upon death, covering bile on anyone standing too close, which also blinds players and attracts the Horde.
Fortunately the Boomer is easy to avoid because it makes a lot of noise; specifically, burping and gurgling sounds. It is also quite large, hence easily spotted and requires only one decent shot to kill which makes it simple to dispatch.
The Smoker
The Smoker is another noisy special infected, distinguishable by its almost constant coughing, hacking and wheezing. Another that explodes upon death, this time releasing a green puff of acrid smoke which causes players to cough and suffer slightly impaired vision when moving through it, but otherwise causes no damage.
The main feature of the Smoker which catches players off guard is its immensely long and powerful tongue, which is capable of grabbing players and pulling them a significant distance from the group. While caught, the player cannot free themselves and instead must rely on a team mate to come to their rescue. The Smoker seems to favour building tops and will hide when players attempt to shoot it.
As with the Boomer, listen for the Smoker’s call and look out for small puffs of green smoke which the beast will emit at various intervals. Once spotted; shoot and shoot to kill.
The Hunter
Fast, agile and strong, the Hunter is one of the most common causes of the cry, “Oh man!” by players when moving through a Left 4 Dead campaign. While the Hunter is fortunately another noise-maker, its ability to leap and pounce can still make it difficult to pin down. Speaking of pinning down, this is exactly what the Hunter does when it successfully pounces a player. The player will remain unable to move or fight back and will require the help of a fellow survivor to get free. The Hunter is capable of inflicting massive damage on a player so team mates will need to move quickly to the rescue. If a player can manage to hit one; the Hunter dies pretty quickly; aside from its speed and nimbleness, it is not too hard to destroy.
Listen for the growl, unmistakeable and dog like and above all else, the scream. Right before a Hunter tries to pounce on someone, it will emit a bone curdling scream. A good strategy is to wait until the scream is heard, then move quickly in any one direction, turning to search for the Hunter as the player moves. Often, multiple shots are required to take down the Hunter, as it is slightly stronger than the Boomer and Smoker.
The Witch
The Witch is identifiable by her child-like cry and is seen rocking back and forth on the ground. She is reasonably easy to avoid by turning off flashlights and sneaking past her, however accidents will happen hence strategy for her is included here. Shooting near her or standing too close to her for too long will startle her and cause her to attack, as will shining flash lights on her or attempting to shoot her directly. It is possible to kill the Witch with a single headshot (an award is obtainable for this) however less experienced players would do well to avoid her as best they can.
Once the Witch attacks, she can literally kill a player with a single hit (or incapacitate on the Easy mode); she is very, very powerful. She will target the player who startled her and will not stop until either she, or the player is dead. This aside, she does not take considerable firepower to take down if the whole team works together. However avoidance remains the best policy for the Witch.
The Tank
Last but certainly not least is the largest of the special infected, the Tank. This monster throws cars and hurls enormous rocks at players which can incapacitate or kill them instantly depending on set difficulty level. The Tank is the only infected, special or normal, that cannot be punched away due to its immense size and strength. This lumbering beast can be killed only one way; firepower, and lots of it. It moves considerably fast for its size, but shooting and moving backward continuously is the best strategy for taking it down without incident (landscape permitting of course).
The Tank appears randomly throughout campaigns and is heralded by dramatic music playing, its horrifying roar and the entire screen shaking when it begins to get closer.
A good strategy for the tank is to set it on fire (using a Molotov cocktail or shooting fuel cans) and then run away from it. Once a tank is on fire, it will die in 30 seconds, whether it is shot or not.
