Tactics

= Tactics for surviving expert mode =

Assuming a certain level of basic skill and familiarity with tactical shooters, this wiki should help you and your fellow survivors get through the expert mode of Left 4 Dead... alive!

Surviving a horde
Infected run fast, come in large numbers, and are often backed up by bosses. This section describes tactics you can use regardless of what you're teammates are doing.

Doors
Always close doors when you find them, then blast a peep-hole through it. You can then safely kill infected through the door. If the hole in the door is big enough, go ahead and use melee through the door. This will knock the infected back, saving the door from immediate destruction, and keep you nice and safe.

NOTE: hunters can knock down doors surprisingly fast and pounce on you, smokers can send their tongue through the tiniest hole in the door, and boomers can blow up the door (and slime you if you are too close to it).

Corners and walls
When the crapola hits the fan, the best cover in this game can be found in a corner, or failing that a wall to your back. You can then use a melee to knock back infected and shoot when you have breathing room.

On top of things
Sadly, being on top of a car, subway, etc. is of negligible value as cover in this game due to the climbing abilities of the infected. In fact, you'll often find yourself in a situation where you are being attacked along 360 degrees, which in most cases is fatal. However, gaining the high ground while making sure your back is covered can buy you a good amount of time, due to the fact that it will take a few seconds for an infected to climb up. Use melee or a well placed round or two to finish off a few of the horde.

Hunter
Before pounce:
 * 1) Wait for him to get close then throw a melee attack. This will stun him. Use weapon fire or two more melee hits to finish him off.
 * 2) A well timed headshot with a hunting rifle or shotgun can stop a hunter mid-pounce. You may also earn an achievement.
 * 3) Unload your weapon...

After pounce (helping the downed teammate):
 * 1) Melee! Always prefer melee as it will stop the damage immediately, reliably, and without causing team-damage.
 * 2) If too far way for melee, head-shots on the hunter are effective.

Smoker
Before strangulation:
 * 1) Unload your weapon

During strangulation (1 sec):
 * 1) Try to head-shot the smoker or just unload on him
 * 2) If he's out of sight, try shooting the tongue itself

After strangulation (helping the downed teammate):
 * 1) Melee. You can melee three things to immediately frees them:
 * 2) Your teammate
 * 3) The tongue
 * 4) The smoker himself
 * 5) Shoot
 * 6) Target the smoker
 * 7) Target his tongue (especially useful when you have no line of sight on the smoker himself)

Boomer
Before bile spit or boomer death explosion:
 * 1) If boomer is too close, you need to melee him then run away to a safe distance before shooting or you'll get slimed and become bait.
 * 2) * CAUTION: you can only melee a boomer twice, a third time will cause him to blow up on you
 * 3) If boomer is sufficiently far away, shoot!

After slimed:
 * Hold your fire! Since you can't see you'll likely shoot your teammates. You need to:
 * Run to a corner
 * Use melee continuously to survive the incoming zombie horde
 * Once your sight clears, mop up with your weapon

After slimed (helping the slimed teammate):
 * Move to the same corner as your unfortunate teammate and help melee back the zombies and shoot if you have a clear line of sight

Witch
What startles the witch?
 * Medium proximity with flashlight. In fact, according to in-game cvars, see console wiki for details, you will find that z_witch_personal_space 100 and z_witch_flashlight_range 400, which suggests flashing her pisses her off at 4 times the normal distance.
 * Relatively close proximity and running (not proven if running or shooting near but not at her really has an impact IMO)
 * Very close proximity and walking softly

Under what situations is startling the witch survivable?
 * Teammate gets between you and her
 * You are sufficiently far away that she loses interest in you before killing you
 * You shut the safe-room door on her
 * You run around like mad through a subway car which seems to slow her down sufficiently

Tank
In general:
 * 1) Listen carefully for the tank, make sure you can distinguish him from a hunter/smoker/boomer. By the time the music changes, or worse the tank is in your line of sight, it is often too late to plan an effective defense
 * 2) Throw a molotov cocktail in its path to set it on fire and slowly eat away all 8000 hitpoints
 * 3) Run and shoot, the intro movie was correct on this point
 * 4) * If the tank is very close, focus entirely on running lest you run into an obstacle and become another statistic
 * 5) * Otherwise, go ahead an open up on it. Be aware that the nearest survivor that shoots the tank is the target
 * 6) Provided you have 40+ hitpoints, it is fairly easy to "kite" a tank. In other words, you can get the tank to follow you without him ever catching up, and yet still have time to put lead/grenades into him. Using this tactic, tanks can reliably be beaten with no casualties (given sufficient running room)
 * 7) The corollary to the previous point is that if you have less than 40 hitpoints you should refrain from shooting and just stay out of the way
 * 8) The tank climbs obstacles much more slowly that he can run, abusing this fact will provide you with more uninterrupted firing time

If the tank is throwing concrete at you:
 * Good news:
 * The tank can't move and throw
 * You'll know when he's doing a throw by the absence of the ground pounding noise
 * Bad news:
 * The tank has perfect aiming accuracy
 * One shot will incapacitate you
 * Non-static geometry such as crates will not block his shots
 * If you do not have suitable cover, you should look at the tank and time your dodging maneuver for the moment he throws the rock. Otherwise the tank will compensate his aim for your dodging and you will go down
 * You may be unable to dodge a rock if you are limping too badly (i.e.: when you have less than 40 hitpoints)

If a teammate goes down (and you are suicidally brave):
 * 1) Melee the tank once to get its attention (it will re-target on you)
 * 2) Immediately pull a "Forest Gump" maneuver

Team tactics
This game hates lone wolves like no other. You need a teammates to cover your six and pull you out of the dung hole. Voice communication is so useful it aught to be a minimum requirement.

Zombie buddies
An effective tactic, especially in tight quarters, is to split your team into a point squad and a rearguard. The squad on point is responsible for eliminating all threats from the front while the rearguard puts the hurt on infected flanking maneuvers. This tactic is especially effective because your zombie buddy is close enough to you that they can knock bosses off of you before they can deal damage to you.

Cornered
Surprisingly, four survivors crammed into one corner works very well. Deploy two of them in a crouched position doing melee while two more stand behind them and unload their weapons.

Lines of fire (and the not so friendly fire)
Important rule of thumb: when in doubt hold your fire and use a melee attack

Consider some real-life situations:
 * An infected slips past you and you give in to the temptation to whip around 180 degrees to gun them down but instead destroy your teammate
 * A teammate is man-handling an infected but you decide to "help" them out, only to miss and reduce the survivor count
 * A boomer slimes you so you shoot blind in a panic, thus killing the two teammates who were trying to cover for you

Also, whenever a survivor is between you and a target rich environment, you should either:
 * Hold fire and ask them to crouch (good players will do this automatically)
 * If they are crouched, inform them you are behind them, then open fire (otherwise they might stand up again when you do not expect it)

Dangerous weapons
The following weapons have relatively large areas of effect and thus cause friendly fire havoc on a regular basis.

Shotguns: do not open fire unless you are in front of your teammates. Generally, do not even try to "help" your teammates by picking off targets that are attacking them. If you must shoot, deliberately "miss" the target to place your shot as far away from your teammate as possible.

Molotovs: this is the single most dangerous weapon to your teammates in the game. Always warn your teammates before deployment and throw it as far as possible. Likewise for fuel tanks you may find in the level.

Pipe bombs: this weapon is dangerous for a different reason than the Molotov. The blast radius is small enough that it's trivial to avoid. What is downright impossible is to avoid the horde of zombies a badly thrown pipe bomb will attract without destroying. Imagine the following scenario: the survivor team is facing a standing army of infected in front of them and suddenly a horde flanks them from the rear. The player named "Genius" throws a pipe-bomb at the infected hitting the flank. This attracts both groups of infected, detonates to kill the flanking group, and leaves the survivors in the midst of an angry mob of infected that were formerly peaceful in the front. Not good.

Dropping down the rabbit hole
This is a source of much agony since infected are often waiting for you at the bottom. You should inform teammates before you jump down and if you are already down there, be aware that teammates will "unexpectedly" drop down from above to intercept your fire.

Teammates left behind
Should someone fall behind and get attacked by a Hunter or Smoker after everyone else has dropped down the rabbit hole, there is still a way to save them. Most walls, ceilings, and floors allow you to shoot through them. The damage you do will be greatly reduced, but you can still end up saving your stranded ally before they are incapacitated.

Medical attention
Should you help fallen comrades get up(and cover the rescuer)?
 * Yes! Remember this game absolutely loves destroying lone wolves and every time your survivor count decrements you are entering a new world of hurt.

When should you help a fallen comrade up?
 * As soon as they fall and the area is clear. It is impossible to help someone up while infected are hitting on you or the fallen comrade.

Once you sustain damage how can you regain your health?
 * 1) Health kit: stabilizes your health and puts you into the green (80 or better hitpoints)
 * 2) Pain pills: temporary health boost, nothing more, but this makes a big difference by letting you run instead of limp and survive potential knock-out blows
 * 3) Dying then getting "rescued", you get 50 hitpoints on rescue

What are the mechanics of getting helped back up?
 * Restores you to 30 hitpoints that decrement over time
 * Only works up to 3 times unless you use a medkit (resets count)

If you die, how do you come back?
 * Your teammates will need to advance a certain distance beyond your body into the level
 * You will need to wait 1 minute
 * Your teammates then need to open the closet you will spawn in to complete the "rescue" of a "new" survivor