Full list of all 65 Left 4 Dead achievements worth 1,500 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 3 DLC packs containing 15 achievements worth 500 Gamerscore.
Kill 53,595 Infected.
Survive all campaigns on Expert.
Kill 1000 Infected with a mounted machine gun.
Survive a campaign with no Survivors taking damage from Special Infected.
Give pain pills to 10 Survivors.
Punch a Hunter as he is pouncing.
Survive an entire campaign using only pistols.
Rescue a Survivor trapped in a closet.
Finish a campaign without ever being healed.
Survive any campaign on Expert.
Survive the Dead Air campaign.
Survive the Blood Harvest campaign.
Shove a Boomer and then kill him without him splashing on anyone.
Drag a Survivor 100 feet with your tongue.
Headshot a Hunter while he's leaping.
All Survivors complete a campaign without being vomited on.
Play an entire campaign with no Survivors taking friendly fire damage.
No Survivors take damage after contacting the rescue vehicle.
Heal 25 Survivors with a first aid kit.
Dole out 5000 total Survivor damage as a Special Infected.
Kill all four Survivors in one life while playing as a Tank.
Pounce two different Survivors in one life as a Hunter.
Revive 50 incapacitated Survivors.
Sneak past all Witches in a campaign without disturbing one.
Cover four Survivors with Boomer bile at once.
As an Infected, incap a Survivor who has entered and left a safe room.
Light a Tank with a Molotov.
Survive a campaign without being incapacitated.
Save another Survivor from a Special Infected while on the ground.
Single-handedly kill a Tank.
Kill a Witch with a single headshot.
Set 101 Infected on fire.
Kill an Infected with a single blow from behind.
Constrict two Survivors in one life as a Smoker.
Leave a safe room to save an incapped teammate and bring them back safely.
Kill a Witch without any Survivor taking damage from her.
Heal a fellow Survivor when your own health is below 10.
Light a Witch with a Molotov.
Survive the No Mercy campaign.
Kill a Tank without it dealing any damage to a Survivor.
Protect any Survivor from an attacking Infected 50 times.
Survive the Death Toll campaign.
Beat a campaign with all 4 Survivors.
Blow up 20 Infected in a single explosion.
Kill 10 Smokers as they are pulling helpless Survivors.
Make 100 headshot kills.
Shove a Hunter off of a pinned and helpless Survivor.
Rescue a Survivor from a Smoker's tongue before he takes damage.
You or another Survivor take no damage after being vomited on by a Boomer.
Free yourself from a Smoker who has grabbed you with his tongue.
Kill 5,359 Infected in the Crash Course campaign.
Win a Versus campaign of Crash Course.
Your team wipes all Survivors after the escape vehicle has opened in Crash Course.
Pounce a Survivor for 25 points of damage in the Crash Course campaign.
Smoker pull a bile-covered Survivor until you hold him during Crash Course.
Your team incapacitates three Survivors within five seconds in the Crash Course campaign.
Survive the Crash Course Campaign.
Restart the generator within 30 seconds of it shutting off in the Crash Course campaign.
Stun a Tank with an explosion in the Crash Course campaign.
As a Tank hit 20 Survivors with a car in the Crash Course campaign.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Complete "The Sacrifice".
Have Bill sacrifice himself for the team.
Have all 3 generators running at once in "The Sacrifice" finale.
Kill a Special Infected with an exploding barrel.