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