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