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