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