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.
Survive a campaign on Expert skill with Realism mode enabled.
Kill a Charger with a melee weapon while they are charging.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
Survive all campaigns on Expert.
Spread cheer by helping a free holiday player survive a campaign.
Plays games with free weekend players and helps them survive a campaign.
Cross the bridge finale in less than three minutes.
Revive 10 dead Survivors with the defibrillator.
As the Charger, bowl through the entire enemy team in a single charge.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Defend yourself at the crashed airliner without taking damage.
Cause 25 gas can drops as a Special Infected.
Kill 15 Infected with a single grenade launcher blast.
Kill a Tank with melee weapons.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Collect 100 gas cans in Scavenge.
In a Survival round, get a medal only using melee weapons.
Rescue Gnome Chompski from the Carnival.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Prove you are stronger than Moustachio.
Honk the noses of 10 Clowns.
Prove you are faster than Moustachio.
Make a Survivor drop a gas can during overtime.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Navigate the sugar mill and reach the safe room without killing any Witches.
Survive the Hard Rain campaign.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Kill 10 swampy Mudmen while they are in the water.
Finish a campaign using only melee weapons.
Decapitate 200 Infected with a melee weapon.
Use a bile bomb on a Tank.
Win a game of Scavenge.
Collect 15 gas cans in a single Scavenge round.
Survive the Parish campaign.
Ignite 50 Common Infected with incendiary ammo.
Use every melee weapon to kill Common Infected.
Survive the Swamp Fever campaign.
Survive the Dark Carnival campaign.
Kill one of each Uncommon Infected.
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 100 Common Infected with the chainsaw.
Deploy an ammo upgrade and have your team use it.
Survive the Dead Center campaign.
As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
As the Charger, grab a Survivor and carry them over 80 feet.
As the Jockey, ride a Survivor for more than 12 seconds.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
As the Jockey, ride the Survivors twice in a single life.
As the Spitter, hit every Survivor with a single acid patch.
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 6 Mutations.
Using the M60, kill 25 infected without letting go of the trigger.
Kill a Tank only with damage from the original Survivors.
Play 5 full games of Scavenge on The Port.
Play the new Midnight Riders song on a jukebox.
Open 5 foot lockers.
Survive The Passing Campaign.
Collect 10 items dropped by a Fallen Survivor.
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.
Complete "The Sacrifice".
Have Bill sacrifice himself for the team.
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 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
Survive for 30 minutes on any official survival map.
Survive The Last Stand campaign on Expert Realism.
Kill the Witch bride with a single shotgun blast on expert difficulty.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Kill 20 Jockeys with the shovel or pitchfork.
Destroy 20 gascans as the Spitter.
As the Spitter, spit on a Survivor who is pinned by a Charger.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
Instantly kill a Survivor as the Charger.
As the Hunter, land a 25 damage pounce.
Survive for 10 minutes on any official map in Versus Survival.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Escape Liberty Mall's Atrium before the first Tank appears
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Kill a pouncing Hunter with a shotgun.
Earn a gold medal on any official survival map.
Destroy a Tank's rock in mid-air.
Earn a silver medal on any official survival map.
Rescue three Survivors from a single rescue closet.
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Discover the hidden room in the Last Stand campaign
On the concert finale, survive until the helicopter arrives without leaving the stage
Revive an incapacitated teammate while a Tank is nearby.
Survive The Last Stand campaign on any difficulty.
Earn a bronze medal on any official Survival map.
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.