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