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