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