Full list of all 65 Left 4 Dead 2 achievements worth 1,500 gamerscore. It takes around 20-25 hours to unlock all of the achievements in the base game.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 15 achievements worth 500 Gamerscore.
Revive 10 dead Survivors with the defibrillator.
Survive all campaigns on Expert.
Kill 10 swampy Mudmen while they are in the water.
Kill 15 Infected with a single grenade launcher blast.
Survive a campaign on Expert skill with Realism mode enabled.
Cross the bridge finale in less than three minutes.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Kill a Tank with melee weapons.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Collect 100 gas cans in Scavenge.
As the Charger, bowl through the entire enemy team in a single charge.
As the Spitter, hit every Survivor with a single acid patch.
Kill a Charger with a melee weapon while they are charging.
In a Survival round, get a medal only using melee weapons.
Cause 25 gas can drops as a Special Infected.
Collect 15 gas cans in a single Scavenge round.
Make a Survivor drop a gas can during overtime.
Prove you are faster than Moustachio.
Survive the Hard Rain campaign.
Win a game of Scavenge.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Navigate the sugar mill and reach the safe room without killing any Witches.
As the Charger, grab a Survivor and carry them over 80 feet.
Honk the noses of 10 Clowns.
As the Spitter, spit on a Survivor being choked by a Smoker.
As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
Survive the Parish campaign.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Ignite 50 Common Infected with incendiary ammo.
Decapitate 200 Infected with a melee weapon.
Survive the Swamp Fever campaign.
Finish a campaign using only melee weapons.
Use every melee weapon to kill Common Infected.
Defend yourself at the crashed airliner without taking damage.
Kill one of each Uncommon Infected.
Deploy an ammo upgrade and have your team use it.
As the Jockey, ride a Survivor for more than 12 seconds.
Survive the Dark Carnival campaign.
Rescue Gnome Chompski from the Carnival.
Prove you are stronger than Moustachio.
Kill 100 Common Infected with the chainsaw.
As the Jockey, ride the Survivors twice in a single life.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
Survive the Dead Center campaign.
Use a bile bomb on a Tank.
Kill a Spitter before she is able to spit.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Play 5 full games of Scavenge on The Port.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Open 5 foot lockers.
Play 6 Mutations.
Using the M60, kill 25 infected without letting go of the trigger.
Kill a Tank only with damage from the original Survivors.
Survive The Passing Campaign.
Play the new Midnight Riders song on a jukebox.
Knock off the heads of 18 infected with the golf club.
Collect 10 items dropped by a Fallen Survivor.
Have all 3 generators running at once in "The Sacrifice" finale.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Kill a Special Infected with an exploding barrel.
Have Bill sacrifice himself for the team.
Complete "The Sacrifice".