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