- Rudolph, the Bloody Nosed Reindeer
[2010 Xmas] Kill a Christmas Crawler with a Crossbow.
- Keep Those Sneakers Off the Floor!
Kill 20 Stalkers with Explosives.
- Cave of Wonder
Beat ThrillsChills on Normal Difficulty
- All shook up
Destroy all (15) Snow Globes
- Gimli That Axe!
Get the Not-a-war-hammer Achievement in Dwarfs!?
- Elephant Gun
Land the killing blow on a Circus Fleshpound with a Pistol.
- Fascist Dietitian
Kill 200 Bloats.
- I love ze Healing not ze Hurting
Heal others for 3000 points of health with the MP5 SMG
- Chicken Farmer
Win a Long Game on Farm on Normal Difficulty.
- Quarter Pounder With Ease
Turn 5 Fleshpounds into Giblets.
- I Like To Watch
Aquire 5 Minutes of "Zed-Time".
- Master Surgeon
As a Medic, Kill 8 Specimens using a Knife in a Single Wave.
- Fiery Personality
Set 3 Hillbilly Gorefasts on fire with the Flare Pistol or Trench Gun
- Assistant Homicide
Kill 2 Circus Stalkers with a Melee weapon to the back in one wave.
- Waste Disposal
Win a Long Game on Biohazard on Normal Difficulty.
- Longshoreman
Beat Fright Yard on Normal Difficulty
- Science Got Done
Win a Long Game on Aperture on Normal Difficulty.
- Lab Cleaner
Win a Long Game on Biotics Lab on Normal Difficulty.
- The Big Hunt
Kill a Circus Scrake with a Crossbow.
- Warehouse Janitor
Win a Long Game on Crash on Normal Difficulty.
- Daytrip
Win a Long Game on Mountain Pass on Normal Difficulty.
- Homer's Heroes
Kill 100 Sirens.
- Too Close For Comfort
Finish off a Fleshpound using a Melee Attack.
- Pub Crawl
Win a Long Game on West London on Normal Difficulty.
- Taking Down the Big Top
Kill 4 Circus Zeds in 1 ZED time chain with a Melee weapon.
- Deck the Halls with Buckets o' Blood
[2010 Xmas] Kill 3 Christmas Zeds in 1 ZED time chain with a Melee weapon.
- I Am Become Death
Kill 5 Hillbilly Zeds in 10 seconds with the Scythe or Axe
- Combat Medic
Kill a zed that has injured a player (M7A3 rifle)
- British Superiority
Kill a zed each with both the Bullpup and FN-Fal
- Back to Work
[2010 Xmas] Kill 20 Christmas Clots in one wave.
- Philanthropist
Give 1,000 Pounds to Teammates who have 50% of Your Cash or Less.
- Self Medicator
In Co-op Mode, Use Syringe on Yourself 100 Times.
- Experimentimillicide
Kill 1,000 Specimens.
- Meet Your Maker!
Kill 1000 Hillbilly Zeds
- Straight Rush
Kill the Patriarch Before he has a Chance to Heal.
- Historical Remnants
Kill 6 Zeds with one magazine on an MKb42, without reloading
- Toasted Jack Frost
[2010 Xmas] Kill the Christmas Scrake with a Fire-based weapon.
- Burning up the Midway
Kill 10 Circus Clots with a Fire-based weapon.
- Let Them Burn
Get 1000 points of burn damage with the MAC-10.
- Clearing Clown Alley
Kill 5 Circus Bloats in one game.
- Random Axe of Kindness
Kill 15 Specimens with a Fire Axe in a Single Wave.
- Sparring with a Master
Kill a Circus Gorefast with a Melee weapon.
- Fending off Mrs. Claws
[2010 Xmas] Kill 3 Christmas Stalkers with a Lever Action Rifle without reloading.
- Seeing Double
Kill 5 Circus Crawlers with a Bullpup in one wave.
- Bloody Yanks
Kill 1 specimen ONLY while expending a full M4 Assault Rifle magazine
- A Bloody Christmas Carol
Kill 15 XMas Clots, 5 xmas Stalkers, 5 XMas Crawlers, 1 XMas Siren and 1 XMas Bloat.
- Who Brings a Gun to a Snow Ball Fight?
[2010 Xmas] Kill a Christmas Husk with any Pistol.
- Experimenticenticide
Kill 100 Specimens.
- Social Outburst
Kill 8 Specimens with One Grenade.
- Merry Friggin Christmas
[2010 Xmas] Kill the Christmas Patriarch.
- Ringmaster
Kill the "Ring Leader" (Circus Patriarch)
- Small Hands
Kill 3 Circus Clots in a wave with the Lever Action Rifle.
- Trick, not Treat
Kill 5 Halloween Specimens with any gun without reloading
- It's Not Easy Being Greasy
Cause a Specimen to Die by Luring them into Bloat Acid.
- Mr. Perky
Get All of your Perks up to Level 5.
- Death To The Mad Scientist
Defeat the Patriarch on Suicidal.
- Hard Boss
Win a Long Game on Offices on Hard Difficulty.
- The Hard War
Complete a Long Game on all 5 Core Maps on Hard Difficulty.
- Suicidal Pub Crawl
Win a Long Game on West London on Suicidal Difficulty.
- Emperor of the Manor
Win a Long Game on Manor on Suicidal Difficulty.
- Alligator Farmer
Win a Long Game on Farm on Suicidal Difficulty.
- Mad Boss
Win a Long Game on Offices on Suicidal Difficulty.
- Lab Professor
Win a Long Game on Biotics Lab on Suicidal Difficulty.
- The Completely Suicidal War
Complete a Long Game on all 5 Core Maps on Suicidal Difficulty.
- Steel Worker
Win a Long Game on Foundry, on Hard Difficulty.
- Man of Steel
Win a Long Game on Foundry, on Suicidal Difficulty.
- Gone Mental
Win a Long Game on Bedlam, on Hard Difficulty.
- Complete Barking
Win a Long Game on Bedlam, on Suicidal Difficulty.
- Raccoon King of the Dark Forest
Win a Long Game on Wyre, on Hard Difficulty.
- Bear King of the Dark Forest
Win a Long Game on Wyre, on Suicidal Difficulty.
- Summer of 2009
Complete a Long Game on all 3 Summer 2009 maps on Hard Difficulty.
- And Back to School
Complete a Long Game on all 3 Summer 2009 maps on Suicidal Difficulty.
- Explosive Personality
As Demolitions, kill 1000 Specimens with the Pipebomb.
- Dot of Doom
Get 25 headshots in a row with the EBR while using the Laser Sight.
- Pound This
Kill 100 Fleshpounds with the AA12.
- Hellish Pub Crawl
Win a Long Game on West London on Hell on Earth Difficulty.
- Demonic King of the Manor
Win a Long Game on Manor on Hell on Earth Difficulty.
- Demon Farmer
Win a Long Game on Farm on Hell on Earth Difficulty.
- Boss from Hell
Win a Long Game on Offices on Hell on Earth Difficulty.
- Scientist from Hell
Win a Long Game on Biotics Lab on Hell on Earth Difficulty.
- Diablo Steel Man
Win a Long Game on Foundry on Hell on Earth Difficulty.
- Commit-ed for life
Win a Long Game on Bedlam on Hell on Earth Difficulty.
- Wolf King of the Dark Forest
Win a Long Game on Wyre on Hell on Earth Difficulty.
- Waste Land
Win a Long Game on Biohazard on Hard Difficulty.
- Waste of Space
Win a Long Game on Biohazard on Suicidal Difficulty.
- Wasted
Win a Long Game on Biohazard on Hell on Earth Difficulty.
- Warehouse Forklift Operator
Win a Long Game on Crash on Hard Difficulty.
- Warehouse Foreman
Win a Long Game on Crash on Suicidal Difficulty.
- Warehouse Manager
Win a Long Game on Crash on Hell on Earth Difficulty.
- Departure Lounge
Win a Long Game on Departed on Hard Difficulty.
- Departure Gate
Win a Long Game on Departed on Suicidal Difficulty.
- Dear Departed
Win a Long Game on Departed on Hell on Earth Difficulty.
- Missed Connection
Win a Long Game on Filth's Cross on Hard Difficulty.
- Train Wreck
Win a Long Game on Filth's Cross on Suicidal Difficulty.
- Pile Up
Win a Long Game on Filth's Cross on Hell on Earth Difficulty.
- That Bloody Well Hurts!
Win a Long Game on Hospital Horrors on Hard Difficulty.
- I'm Dying Here!
Win a Long Game on Hospital Horrors on Suicidal Difficulty.
- Not Dead Yet!
Win a Long Game on Hospital Horrors on Hell on Earth Difficulty.
- Crushed Ice
Win a Long Game on Icebreaker on Hard Difficulty.
- Iceberg
Win a Long Game on Icebreaker on Suicidal Difficulty.
- Comet
Win a Long Game on Icebreaker on Hell on Earth Difficulty.
- Mountaineer
Win a Long Game on Mountain Pass on Suicidal Difficulty.
- Park Ranger
Win a Long Game on Mountain Pass on Hell on Earth Difficulty.
- Private Security
Win a Long Game on Suburbia on Hard Difficulty.
- Vigilante
Win a Long Game on Suburbia on Suicidal Difficulty.
- SWAT
Win a Long Game on Suburbia on Hell on Earth Difficulty.
- Burst Pipe
Win a Long Game on Waterworks on Hard Difficulty.
- Pressure Failure
Win a Long Game on Waterworks on Suicidal Difficulty.
- Floodgate to Hell
Win a Long Game on Waterworks on Hell on Earth Difficulty.
- Pound Cake
Complete all new map achievements on Hard Difficulty.
- Fruit Cake
Complete all new map achievements on Suicidal Difficulty.
- Devil Cake
Complete all new map achievements on Hell On Earth Difficulty.
- Silent Night, Evil Night
Win a Long Game on Santa's Evil Lair on Hard Difficulty.
- I'm Dreaming of a Red Christmas
Win a Long Game on Santa's Evil Lair on Suicidal Difficulty.
- Grandma got Eaten by a Reindeer
Win a Long Game on Santa's Evil Lair on Hell on Earth Difficulty.
- Still Alive
Win a Long Game on Aperture on Hard Difficulty.
- This is a Triumph
Win a Long Game on Aperture on Suicidal Difficulty.
- I'm Making a Note Here, Huge Success
Win a Long Game on Aperture on Hell on Earth Difficulty.
- Golden Potato
Get into GLaDOS' core on Aperture.
- Dog and Pony Show
Win a Long Game on Abusement Park on Hard Difficulty.
- 3 Ring Circus
Win a Long Game on Abusement Park on Suicidal Difficulty.
- On Top of the Big Top
Win a Long Game on Abusement Park on Hell on Earth Difficulty.
- Juggling Act
Drop 5 different Tier 2 weapons in one wave.
- Zed October
Win a Long Bedlam Match During the Halloween Event on Hard
- This is No Ordinary Rabbit!
Kill 25 Halloween Scrakes in Bedlam
- Rule The Roost
Get all 6 achievements and unlock Commando Chicken
- Burning Irony
Kill 15 Husks with the Husk Cannon
- Highlander
Kill a Scrake, a Fleshpound, and the Patriarch with the Claymore Sword within one map
- Italian Meat Pasta
Kill 12 zeds with a full magazine from the Combat Shotgun
- Stay Frosty
Beat Ice Cave on Hard Difficulty
- On the Rocks
Beat Ice Cave on Suicidal Difficulty
- Anti Freeze
Beat Ice Cave on Hell on Earth Difficulty
- Fugly
Kill one of each type of zed in one round (HSG Shotgun)
- The Big One
Kill 2 scrakes with one shot (M99)
- Stuck in Limbo
Beat Hellride on Hard Difficulty
- Demonic Road
Beat Hellride on Suicidal Difficulty
- Devil's Co-pilot
Beat Hellride on Hell on Earth Difficulty
- Trench Warfare
Set a total of 200 Zeds on fire with the Trench Gun in Hillbilly Horror
- Second Cousins
Beat Hillbilly Horror on Hard Difficulty
- First Cousins (Once Removed)
Beat Hillbilly Horror on Suicidal Difficulty
- First Cousins
Beat Hillbilly Horror on Hell on Earth Difficulty
- Have my axe
Kill 30 Fleshpounds with the Dwarfs!? axe with back attacks
- One Small Step for Man
Kill 500 Zeds with the Schneidzekk Medic Gun while you are falling
- Game Over, Man!
Have 20 Zeds you slowed with the Z.E.D. gun killed
- Attempting Re-entry
Beat Moonbase on Hard Difficulty
- Amusing Death
Beat Moonbase on Suicidal Difficulty
- One Giant Leap (Back) for Mankind
Beat Moonbase on Hell on Earth Difficulty
- Modified Psychoacceleration Achiever
Beat Steamland on Hard Difficulty
- Fractional Neutron Activator
Beat Steamland on Suicidal Difficulty
- Advanced Omega Wave Resonance Explorer
Beat Steamland on Hell on Earth Difficulty
- Simplified Force Adhesion Afficianado
Beat Steamland in Objective Mode on Normal Difficulty
- Oscillating Hydrogen Transition Achiever
Beat Steamland in Objective Mode on Hard Difficulty
- Alpha Wave Osteooxidation Activator
Beat Steamland in Objective Mode on Suicidal Difficulty
- Tachyon Cytoneutralization Explorer
Beat Steamland in Objective Mode on Hell on Earth Difficulty
- Hide and go Puke
[2013 Summer] Destroy all the Pukey the Clown dolls
- Turbo Executioner
Kill 5 zeds in ZED time without reloading with Dr. T's LDS or Bullpup
- Mrs. Punkd
Get 4 of 6 of the 2013 Summer Event in-game level Achievements, one Standard and one Objective Mode map completion Achievement, plus the Punk'd Achievement to unlock Steampunk Mrs. Foster
- Gang Crew
Beat Fright Yard on Hard Difficulty
- Stevedore
Beat Fright Yard on Suicidal Difficulty
- Wharfinger
Beat Fright Yard on Hell on Earth Difficulty
- Truck Driver
Beat Fright Yard in Objective Mode on Hard Difficulty
- Crane Operator
Beat Fright Yard in Objective Mode on Suicidal Difficulty
- Shipping Magnate
Beat Fright Yard in Objective Mode on Hell on Earth Difficulty
- Claw Machine Master
Attach the crane hook within 125 seconds
- Ex-scientist
Collect all the bile without a contamination
- 777
Win Fuel on the first try
- Blinding Big Brother
Destroy all 30 Cameras
- Fire and Forget
Kill a Halloween Fleshpound and Scrake in the same explosion with the Seal Squeal Harpoon Bomber or the LAW
- Under The Weather
Use Bile or the Flamethrower to kill one of each Halloween Zed
- Death
Beat Hell on Normal Difficulty
- King Minos
Beat Hell on Hard Difficulty
- Cerberus
Beat Hell on Suicidal Difficulty
- Lucifer
Beat Hell on Hell on Earth Difficulty
- Agnosia
Beat Forgotten on Hard Difficulty
- Amnesia
Beat Forgotten on Suicidal Difficulty
- Dementia
Beat Forgotten on Hell on Earth Difficulty
- No Time for Love, Dr. Jones
Win a short round on KF-Hell playing as or with Harchier Spebbington
- Home Brewer
Beat Siren's Belch on Normal Difficulty
- Micro Brewer
Beat Siren's Belch on Hard Difficulty
- Master Brewer
Beat Siren's Belch on Suicidal Difficulty
- Trappist Monk
Beat Siren's Belch on Hell on Earth Difficulty
- Oktoberfest Master
Collect all the Beer Steins
- Squire
Beat Stronghold on Hard Difficulty
- Prince
Beat Stronghold on Suicidal Difficulty
- King
Beat Stronghold on Hell on Earth Difficulty
- Rich Evil Uncle
Collect all the Treasure Bags
- Cattle Class
Beat Transit on Normal Difficulty
- Economy Comfort
Beat Transit on Hard Difficulty
- Business Class
Beat Transit on Suicidal Difficulty
- First Class
Beat Transit on Hell on Earth Difficulty
- Day-trip
Beat Transit in Objective Mode on Normal Difficulty
- Long weekend
Beat Transit in Objective Mode on Hard Difficulty
- Serious vacation
Beat Transit in Objective Mode on Suicidal Difficulty
- Moved to Paris!
Beat Transit in Objective Mode on Hell on Earth Difficulty
- Doctor WHO??
Transit - Get all Objective achievements AND beat KFO Transit on Hard or above to unlock Dr Rachel Clamely.
- Gone clubbing
Beat Clandestine on Normal Difficulty
- Rack 'em up
Beat Clandestine on Hard Difficulty
- Burned out
Beat Clandestine on Suicidal Difficulty
- Hangover from Hell
Beat Clandestine on Hell Difficulty
- Skull Cracker
Clandestine - Destroy 30 skulls
- Cavern of Pain
Beat ThrillsChills on Hard Difficulty
- Grotto of Terror
Beat ThrillsChills on Suicidal Difficulty
- Hollow of Horror
Beat ThrillsChills on Hell Difficulty