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