Achievement Unlocked

Revive 50 incapacitated Survivors.

Guide
Once a Survivor are lying on the ground you have to walk up and revive him by pressing "A".

Heal 25 Survivors with a first aid kit.

Guide
To heal, press right on your d-pad to choose your health pack, move close to the Survivor you want to heal and hold the RT button.

Give pain pills to 10 Survivors.

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Press right on your d-pad to choose your pills, move close to the Survivor you want to give pills and press the RT button.

Protect any Survivor from an attacking Infected 50 times.

Guide
To protect a Survivor you have to kill an Infected that is attacking him/her. This can easily be boosted when a Survivor get vomited on by a Boomer. Once the horde of Infected attacks the Survivor, fire at will. Should be done on Easy difficulty so that you don't kill the Survivor with friendly fire.

Punch a Hunter as he is pouncing.

Guide
Move close to a Hunter and melee it by pressing the LT button when it pounces.

Kill a Witch with a single headshot.

Guide
This one can be a tricky. Play on easy difficulty to get this one fast. Run up to a witch with your (auto) shotgun. Once you are close to the Witch, take your time to aim for the Witch's head. Then fire away. You don't have to kill the Witch with a single shot, you just have to make the final kill to the head.
Remember you have to get the Witch's attention before shooting her. Wait for her eyes to turn red.

No Survivors take damage after contacting the rescue vehicle.

Guide
This can be done on the Death Toll finale.
I don't take credits for this method as I didn't come up with it myself. The video, though, I participated in.

Watch this video to see how:

Rescue a Survivor from a Smoker's tongue before he takes damage.

Guide
Easiest way to get this is to melee (LT button) the Survivor when the Smoker grabs him/her with its tongue. If you're too far away then either kill the Smoker or try firing at the Survivor (the Survivor will not be damaged as long as the Smoker's tongue is holding on).

You or another Survivor take no damage after being vomited on by a Boomer.

Guide
The easiest trick to do this is to lure a Boomer outside a safe room and close the door. Then let the Boomer vomit on you through the door.
Remember to do this in the safe room at the beginning of the level, not the safe room in the end as the game might end when you close the door.

Another trick is to back up in a corner and use the melee attack (LT button). This will push the Infected away before they manage to hurt you.

Survive an entire campaign using only pistols.

Guide
This is eaily done in single player on easy difficulty. Always look for an extra pistol to pick up. Two pistols makes it alot easier.

Rescue a Survivor trapped in a closet.

Guide
Can not be done in single player. Either play with a friend in split-screen or online with other friends. Once a Survivor is killed they will automaticly spawn in a closet after a couple of minutes. You will find them once they spawn by following their orange silhouette.

Shove a Hunter off of a pinned and helpless Survivor.

Guide
Once a Hunter jumps a Survivor run up and melee it off by pressing the LT button.

Free yourself from a Smoker who has grabbed you with his tongue.

Guide
A soon as a Smoker grabs you with its tongue, press the LT button to melee attack. Or you can try shooting at its tongue. You can try killing the Smoker, but that will be a bit harder.

Kill 10 Smokers as they are pulling helpless Survivors.

Guide
You have to kill the Smoker. Simply saving the Survivor isn't enough. When a Survivor is grabbed by the Smoker, aim at the Smoker and take it out.

Set 101 Infected on fire.

Guide
This can be done by throwing a molotov or by firing at the red gas cans that are scattered around in the game.
Pick up a molotov and wait for either a horde of Infected attacking, or when a Boomer vomits on a Survivor or when the Infected are alerted otherwise during game play. Choose the molotov by pressing left on the d-pad and throw it towards the Infected as they are storming in.
You can also pick up the gas can and place them around. A well placed gas can are also usefull when the hordes attack. Simply fire at the gas can and it will explode.

Sneak past all Witches in a campaign without disturbing one.

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All you have to do is play through an entire campaign without arousing the witch. This is kind of difficult in single player, as the AIs most likely will mess it up and piss the witch off.
I've even tried this in split-screen and two AIs, but that didn't go to well either. Try doing this one without any AIs.

Single-handedly kill a Tank.

Guide
See Tankbusters

Kill a Tank without it dealing any damage to a Survivor.

Guide
This can be done in single player on Easy difficulty on the Death Toll campaign, level 5 Boathouse Finale.
First start the game on Expert difficulty and kill the AIs. Press 'start' to make a vote, then vote for a difficulty change. Change difficulty to medium.
Then make your way through the house across the street from where you exit the safe room, while killing all the Infected. Once you go through the house and exit it you should come to a large open area. A tank should spawn here (sometimes it doesn't , so you have to start over). If it does, press 'start' and vote for a difficulty change, and make it easy this time. All you have to do now is kill the tank, which should be... easy... on easy settings.

Play an entire campaign with no Survivors taking friendly fire damage.

Guide
This can be done in single player. Play through a campaign with easy difficulty. The AIs never shoots at you unless you run in cross of fire. So watch where you put your foot. Also be careful where you are aiming at. You are most likely to screw this one up long before the AIs.

Beat a campaign with all 4 Survivors.

Guide
Can be done in single player. Play through a campaign with easy difficulty. Be sure to pick up health packs and pills along the way. This will be usefull in case you have to heal yourself or the AIs.
Going through any campaign for this achievement should be easy, the only place you can screw up are in the finales. Since you are playing on easy difficulty you can take alot of damage. So when the rescue arrives at the end, help out the AIs. They tend to slow down and mess around with the Infected and most likely get busted by a Special Infected. So make sure you help them before jumping onboard the rescue vehicles.

Finish a campaign without ever being healed.

Guide
Can be done in single player, even though it can be a bitch. Play through a campaign on easy difficulty.
The bitchy part about playing this on single player is that the other Survivors will always try to heal you. If they try to heal you, simply press right on your d-pad to select your own med pack. Then switch back to your weapon. This gets quite annoying because they will use any opportunity to heal you.
So it will be easier to do this with more players.

Kill a Witch without any Survivor taking damage from her.

Guide
See Cr0wned

Kill 1000 Infected with a mounted machine gun.

Guide
This can be done on single player in any of the finales, as there will be a machine gun there. Make sure you pick up a pipebomb and, if possible, locate where other pipebombs are lying around. Alert the hordes by contacting the rescue vehicle. As the horde rush in, throw the pipebomb and aim at the pipebomb with the machine gun. The Infected will swarm around the pipebomb. Now, fire at will!
Use the pimpbomb trick whenever you come across a machine gun.

I spent about half an hour on the No Mercy campaign, Rooftop Finale before getting this achievement. But I reloaded the level when the second and last tank appears before the rescue chopper comes to your aid and did everything over again.

Blow up 20 Infected in a single explosion.

Guide
Pick up a pipebomb and wait for a horde to attack, then throw the pipebomb. Boom, achievement should unlock.
Another trick is to let the Boomer vomit on you, then you wait for the horde and throw the pipebomb.

Kill 53,595 Infected.

Guide
You can get this by playing through any campaing 54 times (as most playthrough generates about 1000 kills). Or you can play online alot.

Or you can do it the "easy" way, which still is time consuming. Start up No Mercy, Rooftop Finale on Expert difficulty. Kill the AIs. Press 'start' and vote to change to easy difficulty. Step out of the safe room and walk up the stairs. Now, be carefull as there will be a Smoker and a Hunter waiting. When they appear, run back down to the safe room and close the door. Wait a little and they will come after you. Kill them through the door. Run back out up the stairs and a Boomer will show up. Go back to the safe room and close the door. The Boomer will follow you, so make sure you are standing close to the door so that it vomits on you through the bars on the door. This will alert the horde.
All you have to do now is melee attack the door (by pressing the LT button), which will kill the Infected. Each horde generates about 25 kills. Which can make it between 50-100 kills pr minute.
If this is boring, simply use a rubber band to hold the LT button down and go to sleep. As long as the Boomer vomits on you, you will generate kills over night while sleeping :P

Heal a fellow Survivor when your own health is below 10.

Guide
Easiest done with another player. Grab a health pack. If your friend has 100 in health then fire a single shot at your him so that you will be able to heal him a little. Then let him shoot at you until your health is down to 9. Now heal your friend.

Survive a campaign without being incapacitated.

Guide
Can be done in single player on easy difficulty. As long as your health doesn't go below 1, you will be fine. Once you are hurt so badly that you fall to the ground, you have to restart the campaign. Be sure you always are carrying a health pack or pills so you are able to heal yourself.

Survive any campaign on Expert.

Guide
See What Are You Trying to Prove?

Survive all campaigns on Expert.

Guide
This achievement is very time consuming. You basicly have to play through an entire campaign on expert difficulty.
Some people claim they did this in single player with AIs. I don't know, you decide to do it on your own or gather a team.
You can still die during game play and restart a level. All that matters is that in the end at least one of you are able to get on to the rescue vehicle on the last level.
And you don't have to do all the campaigns in one playthrough. But each individual campaign must be done in one playthrough.

NOTE: Some claim you have to survive and get on the rescue vehicle in order to get this achievement. I died and still got it. I guess it's up to the game's mood if you get it or not when dead.

Here are a few tips and hints:

- Always make sure you carry a health pack/pills and a pipebomb/molotov.
- Save your ammo. Running out of ammo is a bitch, unless you have two pistols. But still!
- Take it slow. Don't rush around corners or through open spaces.
- Clean the streets of Infected from a distance.
- Always stick together as a group. Never run on your own. That will end badly.
- If a member of your team is incapacitated, don't just leave him. Help him, cause you will need him (even though he will spawn a few minutes after death).
- Heal your badly wounded friends if you have enough health yourself.
- Beware of friendly fire!
- For God's sake, don't go after this achievement without a mic! Being able to talk and communicate with your team is the basis for this achievement. So communicate, communicate, communicate!
- Do NOT leave the game during a play. First of all, each campaign has to be done in one playthrough! Second of all that is just a big fuck off to you for letting down the other players. Especially if you have been playing for hours.

Survive a campaign with no Survivors taking damage from Special Infected.

Guide
This is, along with Stomach Upset, a messed up achievement. Not being damaged by a Special Infected through an entire campaign takes a miracle. Good luck with this one.

Special Infected: the Boomer, the Smoker, the Hunter, the Tank and the Witch.

I've heard that you can be vomited on by a Boomer, as long as you're not damaged by any of the Infected attacking you. But my bet is that if a Boomer vomits on you, you are basicly busted.
The Smoker can also grab you with its tongue as long as you quickly melee it off or shoots the tongue off.

To do this, play on easy difficulty and keep your eyes and ears open. Also play with full caption (press 'start', go into settings and video settings, turn on Full captions). This way a text will pop up everytime a Special Infected is close.

Light a Witch with a Molotov.

Guide
Simply throw a molotov on a Witch.

Light a Tank with a Molotov.

Guide
Simply throw a molotov on a Tank.

Kill an Infected with a single blow from behind.

Guide
Do this on the easy difficulty. Run up on an Infected (not a Special Infected!) from behind and melee it (press the LT button) in its neck. This will instantly kill it.

All Survivors complete a campaign without being vomited on.

Guide
This is, along with Nothing Special, a messed up achievement. It's basicly impossible not to be vomited on. Boomers always lurk around corners surprising you with its love fluid. So good luck with this one!
To do this, play on easy difficulty and keep your eyes and ears open. Also play with full caption (press 'start', go into settings and video settings, turn on Full captions). This way a text will pop up everytime a Boomer is close.

Make 100 headshot kills.

Guide
It is basicly not worth boosting this achievement. You will get it anyways if you are planning to get all the other achievements, as you probably will do more than 10000 headshots by the time you are done with the game.

Still, if you want to boost this, use the same technique showed in Zombie Genocidest. This time, instead of melee, aim at the heads of the Infected and fire away. Use the M60 or shotgun. You will unlock this achievement quite quickly this way.

Headshot a Hunter while he's leaping.

Guide
I really have no concrete tip for this one. You just have to wait for a Hunter, wait for it to jump and shoot it in the head while it is in the air. You don't have to kill it, you just have to hit in the head.
I can assume this can be done while hiding in a safe room (like in Zombie Genocidest and Brain Salad). This way the Hunter wont be able to take you down. Aim at its head through the bars.

Survive the No Mercy campaign.

Guide
Play through the No Mercy campaign and get on the rescue vehicle.
Can be done on any difficulty.

Leave a safe room to save an incapped teammate and bring them back safely.

Guide
Do this with a friend. Shoot and hurt him until he is incapacitated outside the safe room. Enter the safe room and go out again. Now save him.

Survive the Death Toll campaign.

Guide
Play through the Death Toll campaign and get on the rescue vehicle.
Can be done on any difficulty.

Survive the Dead Air campaign.

Guide
Play through the Dead Air campaign and get on the rescue vehicle.
Can be done on any difficulty.

Survive the Blood Harvest campaign.

Guide
Play through the Blood Harvest campaign and get on the rescue vehicle.
Can be done on any difficulty.

Save another Survivor from a Special Infected while on the ground.

Guide
This means you yourself have to be incapacitated, then one of the other Survivers either get jumped by a Hunter or grabbed by a Smoker. Then you save the Survivor by killing the Special Infected.

I found this easily done in versus mode game online.

Or you can play with a friend and do this:
You both play as Survivors. Kill off the two AIs. Clear an area of Infected, then make your friend incapacitate you. You should now be lying on the ground. Now you just wait for either a Smoker or Hunter to appear. Odds that they will attack you are small as they will go for the moving target. So your friend has to get their attention. As soon as a Smoker or a Hunter grabs your friend, kill it off and save him.

Shove a Boomer and then kill him without him splashing on anyone.

Guide
Trick here is to get in close enough to melee him (by pressing the LT button), the quickly backing off so that if it vomits, it wont hit you. Then kill it. I preferred doing this with the auto shotgun, as it kills quite nicely and fast.
Remember that none of the other Survivors should be standing close to the Boomer when trying this. I didn't make it playing in single player, cause the AIs always got too close. It works better when playing with other players.

Drag a Survivor 100 feet with your tongue.

Guide
Do this with a friend. Start a game where you play the Infected and him a Survivor. Let him kill the other AIs. Let him kill you until you spawn as a Smoker. Find a nice large open area and move away from eachother. Once on the opposite side of eachother you can grab him with your tongue and drag him over to you.

For a challenge, get this achievement online in versus mode with other players.

Constrict two Survivors in one life as a Smoker.

Guide
This means you have to grab a Survivor with your tongue and damage the Survivor.
Do this with a friend. Start a game where you play the Infected and him a Survivor. Let him kill the other AIs except one. Let him kill you until you spawn as a Smoker. Now, grab the AI with your tongue and kill him. Once he is dead grab your friend.

For a challenge, get this achievement online in versus mode with other players.

Cover four Survivors with Boomer bile at once.

Guide
This has to be done in one vomit. Meaning you have to cover all Survivors in one go. This is easily done when the Survivors are constricted in to small areas, such as small rooms or small hall ways.
Can be done with friends where they play Survivors and gather up closely enough for you to vomit on them.

For a challenge, get this achievement online in versus mode with other players.

Pounce two different Survivors in one life as a Hunter.

Guide
Use same procedures as Big Drag and Chain Smoker

Kill all four Survivors in one life while playing as a Tank.

Guide
This one is very tricky. You have to knock out all 4 Survivors (you don't have to kill them, incapacitating them is enough) without dying. It has to be done in one life. If you are killed it doesn't count. Tanks are slow as hell, so chasing down the Survivors is hopeless. Your best option is to be able to sneak attack them and knock them off their feet. There are two ways to attack with the tank: 1. hit them (RT button) 2. throw rocks at them (LT button). Throwing rocks at them from a distance works well. However, if they have full health you are most likely not gonna be able to kill them.

So, use the same procedure as Big Drag, Chain Smoker and Double Jump. But this time start the game on any Finale level. You will eventually spawn as a Tank there. You can do this by playing with a friend as a Survivor and 3 AIs. Even though it's recommendable to do it with two friends as Survivors, as the AIs are good at aiming and will kill you fast.

Dole out 5000 total Survivor damage as a Special Infected.

Guide
Playing online in versus mode should get you this achievement in a day or two. Simply play as an Infected and deal out damage to the Survivors.
This was the funniest achievement imho. Just too bad it was to easy to achieve.

As an Infected, incap a Survivor who has entered and left a safe room.

Guide
A Survivor has to enter the safe room, then leave it and get incapacitated. Simply revive him and you should get it.
Can be done with a friend where he enters the room, gets out and you simply shoot him down.