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