ACHIEVEMENT - HOW TO UNLOCK
A RIDE DENIED - Kill a Jockey within 2 seconds of it jumping on a Survivor.
A SPITTLE HELP FROM MY FRIENDS - As the Spitter, spit on a Survivor being choked by a Smoker.
ACID REFLEX - Kill a Spitter before she is able to spit.
ARMORY OF ONE - Deploy an ammo upgrade and have your team use it.
BACK IN THE SADDLE - As the Jockey, ride the Survivors twice in a single life.
BARREL ROLLED - Kill a Special Infected with an exploding barrel.
BEAT THE RUSH - In a Survival match, get a medal only using melee weapons.
BRIDGE BURNER - Survive the Parish campaign.
BRIDGE OVER TREBLED SLAUGHTER - Cross the bridge finale in less than 3 minutes.
BURNING SENSATION - Ignite 50 Common Infected with incendiary ammo.
CACHE AND CARRY - Collect 15 gas cans in a single Scavenge match.
CHAIN OF COMMAND - Kill 100 Common Infected with the chainsaw.
CHAOS GENERATOR - Have all 3 generators running at once in "The Sacrifice" finale.
CL0WND - Honk the noses of 10 Clowns.
CLUB DEAD - Use every melee weapon to kill Common Infected.
CONFEDERACY OF CRUNCHES - Finish a campaign using only melee weapons.
Connecting Fight - Play a Versus game on Dead Air from start to finish.
CRASS MENAGERIE - Kill one of each Uncommon Infected.
DEAD IN THE WATER - Kill 10 swampy Mudmen while they are in the water.
DISMEMBERMENT PLAN - Kill 15 Infected with a single grenade launcher blast.
FRIED PIPER - Use a Molotov to burn a Clown leading at least 10 Common Infected.
FUEL CRISIS - Make a Survivor drop a gas can during overtime.
GAS GUZZLER - Collect 100 gas cans in Scavenge.
GAS SHORTAGE - Cause 25 gas can drops as a Special Infected.
GONG SHOW - Prove you are stronger than Moustachio.
GREAT EXPECTORATIONS - As the Spitter, hit every Survivor with a single acid patch.
GUARDIN' GNOME - Rescue Gnome Chompski from the Carnival.
HEAD HONCHO - Decapitate 200 Infected with a melee weapon.
HEARTWARMER - In a Versus match, leave the saferoom to defibrillate a dead teammate.
HUNTING PARTY - Win a game of Scavenge.
KILL BILL - Have Bill sacrifice himself for the team.
LEVEL A CHARGE - Kill a Charger with a melee weapon while they are charging someone.
LONG DISTANCE CARRIER - As the Charger, grab a Survivor and carry them over 80 feet.
MEAT TENDERIZER - As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
MIDNIGHT RIDER - Survive the Dark Carnival campaign.
PRICE CHOPPER - Survive the Dead Center campaign.
QUALIFIED RIDE - As the Jockey, ride a Survivor for more than 8 seconds.
RAGIN' CAJUN - Survive the Swamp Fever campaign.
ROBBED ZOMBIE - Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
RODE HARD, PUT AWAY WET - As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
SACRIFIZZLE - As a Special Infected, incap someone who is trying to sacrifice themselves.
SCATTERING RAM - As the Charger, bowl through the entire enemy team in a single charge.
SCAVENGER HUNT - Stop the enemy team from collecting any gas cans during a Scavenge match.
SEPTIC TANK - Use a bile grenade on a Tank.
SHOCK JOCK - Revive 10 dead Survivors with the defibrillator.
SOB STORY - Navigate the sugar mill and reach the safe room without killing any Witches.
SPIT HAPPENS - As the Spitter, hit every Survivor with a single acid patch.
STACHE WHACKER - Prove you are faster than Moustachio.
STILL SOMETHING TO PROVE - Survive all campaigns on Expert.
Stream Crosser - Survive the Cold Stream campaign on any difficulty.
STRENGTH IN NUMBERS - Form a team and beat an enemy team in 4v4 Versus or Scavenge.
TANK BURGER - Kill a Tank with melee weapons.
THE QUICK AND THE DEAD - Revive 10 incapacitated Survivors while under the speed boosting effects of adrenaline.
THE REAL DEAL - Survive a campaign on Expert difficulty with Realism mode enabled.
Valve Gift Grab 2011 – L4D2 - Collect three gifts dropped by Special Infected in Versus Mode.
VIOLENCE IN SILENCE - Navigate the impound lot and reach the cemetary safe room without tripping any alarms.
WEATHERMAN - Survive the Hard Rain campaign.
WING AND A PRAYER - Defend yourself at the crashed airliner without taking damage.

"The Passing" achievements
ACHIEVEMENT - HOW TO UNLOCK
Torch Bearer (20 points) - Survive The Passing Campaign.
Wedding Crasher (30 points) - As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Til It Goes Click (20 points) - Using the M60, kill 25 infected without letting go of the trigger.
Grave Robber (25 points) - Collect 10 items dropped by a Fallen Survivor.
Mutant Overlord (30 points) - Play 6 Mutations.
Fore! (25 points) - Knock off the heads of 18 infected with the golf club.
Killing 'Em Swiftly To This Song (20 points) - Play the new Midnight Riders song on a jukebox.
Kite Like A Man (30 points) - Kill a Tank only with damage from the original Survivors.
Cache Grab (20 points) - Open 5 foot lockers.
Port Of Scavenge (30 points) - Play 5 full games of Scavenge on The Port points.