Full list of all 101 Left 4 Dead 2 achievements. It takes around 80-100 hours to unlock all of the achievements in the base game on Windows.
The base game contains 52 achievements, and there are 7 DLC packs containing 49 achievements.
In a Survival round, get a medal only using melee weapons.
Make a Survivor drop a gas can during overtime.
Cause 25 gas can drops as a Special Infected.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
As the Charger, grab a Survivor and carry them over 80 feet.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Revive 10 dead Survivors with the defibrillator.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
As the Spitter, spit on a Survivor being choked by a Smoker.
Kill a Charger with a melee weapon while they are charging.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Collect 100 gas cans in Scavenge.
Kill a Tank with melee weapons.
Collect 15 gas cans in a single Scavenge round.
Survive all campaigns on Expert.
Cross the bridge finale in less than three minutes.
Survive the Parish campaign.
Survive the Hard Rain campaign.
Navigate the sugar mill and reach the safe room without killing any Witches.
Kill 100 Common Infected with the chainsaw.
Kill 10 swampy Mudmen while they are in the water.
Defend yourself at the crashed airliner without taking damage.
Kill 15 Infected with a single grenade launcher blast.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
Survive the Swamp Fever campaign.
Finish a campaign using only melee weapons.
Survive a campaign on Expert skill with Realism mode enabled.
Survive the Dead Center campaign.
Plays games with free weekend players and helps them survive a campaign.
Decapitate 200 Infected with a melee weapon.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Honk the noses of 10 Clowns.
Ignite 50 Common Infected with incendiary ammo.
As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
Survive the Dark Carnival campaign.
Rescue Gnome Chompski from the Carnival.
Prove you are faster than Moustachio.
Prove you are stronger than Moustachio.
Use a bile bomb on a Tank.
Use every melee weapon to kill Common Infected.
Kill one of each Uncommon Infected.
Deploy an ammo upgrade and have your team use it.
As the Charger, bowl through the entire enemy team in a single charge.
Kill a Spitter before she is able to spit.
Win a game of Scavenge.
As the Jockey, ride a Survivor for more than 12 seconds.
Stop the enemy team from collecting any gas cans during a Scavenge round.
As the Spitter, hit every Survivor with a single acid patch.
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.
Spread cheer by helping a free holiday player survive a campaign.
Open 5 foot lockers.
Collect 10 items dropped by a Fallen Survivor.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Play 6 Mutations.
Play 5 full games of Scavenge on The Port.
Survive The Passing Campaign.
Knock off the heads of 18 infected with the golf club.
Using the M60, kill 25 infected without letting go of the trigger.
Play the new Midnight Riders song on a jukebox.
Kill a Tank only with damage from the original Survivors.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Complete "The Sacrifice".
Kill a Special Infected with an exploding barrel.
Have Bill sacrifice himself for the team.
Have all 3 generators running at once in "The Sacrifice" finale.
Survive the Cold Stream campaign on any difficulty.
Play a Versus game on Dead Air from start to finish.
Collect three gifts dropped by Special Infected in Versus Mode.
Kill 53,599 infected. You made sure the dead won't rise anymore!
Destroy 20 gascans as the Spitter.
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Survive for 10 minutes on any official map in Versus Survival.
Discover the hidden room in the Last Stand campaign
Kill 20 Jockeys with the shovel or pitchfork.
Kill the Witch bride with a single shotgun blast on expert difficulty.
Instantly kill a Survivor as the Charger.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
As the Hunter, land a 25 damage pounce.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Survive The Last Stand campaign on Expert Realism.
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
Earn a gold medal on every official survival map.
Earn a silver medal on every official survival map.
Earn a bronze medal on every official survival map
Revive an incapacitated teammate while a Tank is nearby.
Destroy a Tank's rock in mid-air.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Survive The Last Stand campaign on any difficulty.
Kill a pouncing Hunter with a shotgun.
As the Spitter, spit on a Survivor who is pinned by a Charger.
Survive for 30 minutes on any official survival map.
Earn a gold medal on any official survival map.
Earn a silver medal on any official survival map.
Earn a bronze medal on any official Survival map.
Rescue three Survivors from a single rescue closet.
On the concert finale, survive until the helicopter arrives without leaving the stage
Escape Liberty Mall's Atrium before the first Tank appears
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.