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