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.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Plays games with free weekend players and helps them survive a campaign.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
As the Spitter, spit on a Survivor being choked by a Smoker.
As the Charger, bowl through the entire enemy team in a single charge.
Cause 25 gas can drops as a Special Infected.
Collect 100 gas cans in Scavenge.
Defend yourself at the crashed airliner without taking damage.
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.
Prove you are stronger than Moustachio.
In a Survival round, get a medal only using melee weapons.
Make a Survivor drop a gas can during overtime.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Survive a campaign on Expert skill with Realism mode enabled.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Survive all campaigns on Expert.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Navigate the sugar mill and reach the safe room without killing any Witches.
Rescue Gnome Chompski from the Carnival.
Honk the noses of 10 Clowns.
Prove you are faster than Moustachio.
Finish a campaign using only melee weapons.
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.
Cross the bridge finale in less than three minutes.
Survive the Parish campaign.
Ignite 50 Common Infected with incendiary ammo.
Survive the Hard Rain campaign.
Survive the Swamp Fever campaign.
Kill a Charger with a melee weapon while they are charging.
As the Charger, grab a Survivor and carry them over 80 feet.
Collect 15 gas cans in a single Scavenge round.
Win a game of Scavenge.
As the Jockey, ride the Survivors twice in a single life.
As the Spitter, hit every Survivor with a single acid patch.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Deploy an ammo upgrade and have your team use it.
Kill 100 Common Infected with the chainsaw.
Kill 15 Infected with a single grenade launcher blast.
Spread cheer by helping a free holiday player survive a campaign.
Kill one of each Uncommon Infected.
Use every melee weapon to kill Common Infected.
Use a bile bomb on a Tank.
As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
Decapitate 200 Infected with a melee weapon.
Survive the Dark Carnival campaign.
As the Jockey, ride a Survivor for more than 12 seconds.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
Survive the Dead Center campaign.
Kill a Spitter before she is able to spit.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Play 5 full games of Scavenge on The Port.
Play 6 Mutations.
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.
Open 5 foot lockers.
Collect 10 items dropped by a Fallen Survivor.
Survive The Passing Campaign.
Knock off the heads of 18 infected with the golf club.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Kill a Special Infected with an exploding barrel.
Have all 3 generators running at once in "The Sacrifice" finale.
Have Bill sacrifice himself for the team.
Complete "The Sacrifice".
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!
Earn a bronze medal on every official survival map
Earn a gold medal on every official survival map.
Earn a silver medal on every official survival map.
Survive for 10 minutes on any official map in Versus Survival.
As the Spitter, spit on a Survivor who is pinned by a Charger.
Destroy 20 gascans as the Spitter.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
Instantly kill a Survivor as the Charger.
Survive for 30 minutes on any official survival map.
Earn a silver medal on any official survival map.
Discover the hidden room in the Last Stand campaign
Kill 20 Jockeys with the shovel or pitchfork.
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Revive an incapacitated teammate while a Tank is nearby.
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
Survive The Last Stand campaign on Expert Realism.
Earn a gold medal on any official survival map.
Earn a bronze medal on any official Survival map.
As the Hunter, land a 25 damage pounce.
Kill a pouncing Hunter with a shotgun.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Rescue three Survivors from a single rescue closet.
On the concert finale, survive until the helicopter arrives without leaving the stage
Kill the Witch bride with a single shotgun blast on expert difficulty.
Escape Liberty Mall's Atrium before the first Tank appears
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Destroy a Tank's rock in mid-air.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Survive The Last Stand campaign on any difficulty.
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.