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