User:Cogsdev/Left 4 Dead

This article is a simple gameplay guide I'm throwing together for spasticnerfbag

Weapons
Weapons are stored in three slots: You can switch between your Main Slot weapon and your Pistol Slot weapon with the Q key, and you can also scroll through weapons with your Mouse Wheel. There are also Miniguns, which cannot be picked up and are mounted on scenery.
 * Main Slot, for things like the Uzi or Shotgun. Selected with the 1 key.
 * Pistol Slot, for your Pistol or Dual Pistols. Selected with the 2 key.
 * Grenade Slot, for a Pipe Bomb or a Molotov Cocktail. Selected with the 3 key.

Pistol (Pistol Slot)
Basic weapon that never runs out of ammo. Normal Infected can take quite a few hits to the body from the Pistol but a headshot will kill them instantly. The Pistol is not very effective against Special Infected, except the Boomer, which it can burst in 2-3 hits. It's your backup weapon, and is very useful for conserving ammunition.

Uzi (Main Slot)
One of the two weapons available at the start of a Campaign. Can kill swarms of Normal Infected at medium range very effectively, can kill most Special Infected quite effectively, and surprisingly accurate. The downsides are that it chews through ammo and the clip is quite small, so you have to reload a lot.

Shotgun (Main Slot)
The other weapon available at the start of a Campaign. Can kill groups of zombies at short to medium range. Packs much more of a punch than the Uzi and uses less ammo, but has to reload a lot. Very effective against Special Infected.

Dual Pistols (Pistol Slot)
When you find a second Pistol, you can wield two for increased firepower. Dual Pistols are much more effective against groups of zombies, but still just as effective at picking off zombies with headshots as you advance. Twice the clip size, twice the firing speed, twice as effective (with twice the reload time, I believe).

Assault Rifle (Main Slot)
One of three weapons found partway through Acts and in later Safehouses in a Campaign. Much more accurate, powerful, ammo-efficient and useful than the Uzi. Cuts through swarms as before, but also able to get headshots and doesn't have to reload as often. Runs out of ammo faster than the Auto Shotgun or the Hunting Rifle, so you should use your Dual Pistols to deal with Normal Infected(unless they swarm, in which case you should definitely use the Assault Rifle). Kills Smokers and Hunters(can be a bit tricky if they jump around too much, though), bursts Boomers and does a good deal of damage to Tanks.

Auto Shotgun (Main Slot)
One of three weapons found partway through Acts and in later Safehouses in a Campaign. More powerful and much more fast-firing than the normal Shotgun. Extremely effective against Tanks and, with some skill, Witches. Weapon of choice for dealing with Special Infected or fighting in close quarters, but takes a bit more skill to use than the Assault Rifle. Runs out of ammo very rarely.

Hunting Rifle (Main Slot)
One of three weapons found partway through Acts and in later Safehouses in a Campaign. Kills all Normal Infected in one shot, kills most Special Infected in about three shots, bullets travel through enemies and it has a scope so you can get headshots on distant targets. Takes a lot of skill to use effectively, but if you get good with it, you can kill Special Infected before they can ever cause a problem and clear out Normal Infected with ease. Reasonably ammo-efficient, owing to small clip and slow rate of fire, although when not using the scope it can be fired very quickly as a sort of panic defense.

Molotov Cocktail (Grenade Slot)
The Molotov Cocktail is an extremely dangerous weapon that should be used with extreme caution. If used correctly, it can protect the Survivors from whole hordes of Normal Infected with a wall of fire. If used incorrectly, it can set the Survivors on fire and cause their demise. Make sure you know what you're doing when you use this.

Pipe Bomb (Grenade Slot)
Much more user-friendly than the Molotov Cocktail, but also less generally useful, the Pipe Bomb can be used to divert the attention of a Normal Infected horde away from the Survivors and into a deathtrap. When thrown, the Pipe Bomb will cause all Normal Infected in the area to follow it and gather around it. Once the Pipe Bomb stops moving, it will wait five seconds, and then explode, killing all the Normal Infected it attracted. Invaluable during any event that involves huge hordes of Normal Infected, and requires little experience to use. Generally not as common as the Molotov Cocktail.

Minigun (Mounted Gun)
Sometimes you will come across a Minigun, an extremely powerful weapon that can cut down hordes of enemies and kill Special Infected with ease. Approach the Minigun and press E to use it. Remember, it takes a second to start spinning before you can fire, and if used too much it will overheat and you won't be able to use it until it cools down. Also, the range of fire is limited by its position, so it's easy for zombies to attack you from behind. Make sure someone is watching your back when you use the Minigun.

Useful Items
Med Kits and Pills are stored in their own slots. Med Kits are equipped with the 4 key, and Painkillers are equipped with the 5 key. As with weapons, you can also scroll to them with the Mouse Wheel. Fuel Cans and Gas Canisters can be picked up and moved around, but while holding them equipping anything else will cause you to drop the Fuel Can or Gas Canister.

Med Kits
Restores a significant amount of health to a Survivor. Use it on yourself by holding Left Mouse Button, use it on others by approaching them and holding Right Mouse Button. Essential to survival, and probably the most important item in the game. You can only carry one Med Kit at a time, so if everyone already has a Med Kit and you encounter extra Kits, you should consider using up your current Kits even if you don't really need to since you probably won't be coming back to the extra Kits again.

Painkillers
Gives significant but temporary health boost. Health given by pills drains slowly over time, and appears in the health bar as vertical lines rather than a solid bar like ordinary health. Pills are used with the Left Mouse Button, and can be given to others with the Right Mouse Button. You automatically equip pills as soon as someone gives you them, and there is no warning when being given pills, which can be quite confusing. You can only carry one bottle of pills at a time, so like Med Kits, you may want to use them even when you already have quite a lot of health if you encounter extra Pills. Try to ensure that everyone has a bottle of Pills at all times, so that they can save themselves from death in an emergency.

Fuel Cans
Can be picked up with E. While holding the can, you can hit things with the can with Right Mouse Button, you can throw the can with Left Mouse Button, or you can drop the can with E. When shot, has the same effect as a Molotov Cocktail. It explodes into flames and sets nearby ground, scenery, survivors and Infected alight. As far as I can tell, fire duration is the same as Molotov Cocktail, although it may be a bit longer. Sets Tanks alight, and the wall of fire it creates is very useful for holding off swarms of zombies as Normal Infected die instantly as soon as they hit the fire and most Special Infected will die very quickly.

Gas Canisters
Can be picked up with E. While holding the canister, you can hit things with the canister with Right Mouse Button, you can throw the canister with Left Mouse Button, or you can drop the can with E. Explodes with the strength of a Pipe Bomb when shot. Comes in two varieties, which seem to have the same properties when shot, but look different. Stuns Tanks, kills Normal Infected instantly and does extreme damage to Special Infected but is hard to use.