Left 4 Dead 2

1. 
   CL0WND

   Honk the noses of 10 Clowns.
   9.8%
2. 
   FRIED PIPER

   Using a Molotov, burn a Clown leading at least 10 Common Infected.
   16%
3. 
   LEVEL A CHARGE

   Kill a Charger with a melee weapon while they are charging.
   8.2%
4. 
   ACID REFLEX

   Kill a Spitter before she is able to spit.
   67%
5. 
   CONFEDERACY OF CRUNCHES

   Finish a campaign using only melee weapons.
   3.5%
6. 
   CRASS MENAGERIE

   Kill one of each Uncommon Infected.
   39%
7. 
   A RIDE DENIED

   Kill a Jockey within 2 seconds of it jumping on a Survivor.
   65%
8. 
   HEAD HONCHO

   Decapitate 200 Infected with a melee weapon.
   24%
9. 
   HEARTWARMER

   In a Versus round, leave the saferoom to defibrillate a dead teammate.
   1.6%
10. 
    STILL SOMETHING TO PROVE

    Survive all campaigns on Expert.
    2.2%
11. 
    THE REAL DEAL

    Survive a campaign on Expert skill with Realism mode enabled.
    2.5%
12. 
    STRENGTH IN NUMBERS

    Form a team and beat an enemy team in 4v4 Versus or Scavenge.
    1.5%
13. 
    DEAD IN THE WATER

    Kill 10 swampy Mudmen while they are in the water.
    17%
14. 
    ROBBED ZOMBIE

    Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
    15%
15. 
    DISMEMBERMENT PLAN

    Kill 15 Infected with a single grenade launcher blast.
    12%
16. 
    BURNING SENSATION

    Ignite 50 Common Infected with incendiary ammo.
    23%
17. 
    ARMORY OF ONE

    Deploy an ammo upgrade and have your team use it.
    51%
18. 
    SHOCK JOCK

    Revive 10 dead Survivors with the defibrillator.
    5.5%
19. 
    THE QUICK AND THE DEAD

    Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
    4.0%
20. 
    CHAIN OF COMMAND

    Kill 100 Common Infected with the chainsaw.
    26%
21. 
    SEPTIC TANK

    Use a bile bomb on a Tank.
    33%
22. 
    CLUB DEAD

    Use every melee weapon to kill Common Infected.
    18%
23. 
    TANK BURGER

    Kill a Tank with melee weapons.
    8.3%
24. 
    BRIDGE OVER TREBLED SLAUGHTER

    Cross the bridge finale in less than three minutes.
    4.4%
25. 
    PRICE CHOPPER

    Survive the Dead Center campaign.
    41%
26. 
    MIDNIGHT RIDER

    Survive the Dark Carnival campaign.
    27%
27. 
    RAGIN' CAJUN

    Survive the Swamp Fever campaign.
    21%
28. 
    WEATHERMAN

    Survive the Hard Rain campaign.
    23%
29. 
    BRIDGE BURNER

    Survive the Parish campaign.
    21%
30. 
    VIOLENCE IN SILENCE

    Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
    9.1%
31. 
    GUARDIN' GNOME

    Rescue Gnome Chompski from the Carnival.
    6.3%
32. 
    SOB STORY

    Navigate the sugar mill and reach the safe room without killing any Witches.
    6.4%
33. 
    WING AND A PRAYER

    Defend yourself at the crashed airliner without taking damage.
    4.4%
34. 
    QUALIFIED RIDE

    As the Jockey, ride a Survivor for more than 12 seconds.
    15%
35. 
    BACK IN THE SADDLE

    As the Jockey, ride the Survivors twice in a single life.
    14%
36. 
    RODE HARD, PUT AWAY WET

    As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
    12%
37. 
    GREAT EXPECTORATIONS

    As the Spitter, hit every Survivor with a single acid patch.
    18%
38. 
    A SPITTLE HELP FROM MY FRIENDS

    As the Spitter, spit on a Survivor being choked by a Smoker.
    10%
39. 
    SCATTERING RAM

    As the Charger, bowl through the entire enemy team in a single charge.
    7.6%
40. 
    MEAT TENDERIZER

    As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
    13%
41. 
    LONG DISTANCE CARRIER

    As the Charger, grab a Survivor and carry them over 80 feet.
    9.7%
42. 
    BEAT THE RUSH

    In a Survival round, get a medal only using melee weapons.
    1.9%
43. 
    HUNTING PARTY

    Win a game of Scavenge.
    5.4%
44. 
    GAS GUZZLER

    Collect 100 gas cans in Scavenge.
    2.0%
45. 
    CACHE AND CARRY

    Collect 15 gas cans in a single Scavenge round.
    4.2%
46. 
    SCAVENGE HUNT

    Stop the enemy team from collecting any gas cans during a Scavenge round.
    5.1%
47. 
    GONG SHOW

    Prove you are stronger than Moustachio.
    4.6%
48. 
    FUEL CRISIS

    Make a Survivor drop a gas can during overtime.
    3.0%
49. 
    GAS SHORTAGE

    Cause 25 gas can drops as a Special Infected.
    1.8%
50. 
    STACHE WHACKER

    Prove you are faster than Moustachio.
    5.0%
51. 
    TORCH BEARER

    Survive The Passing Campaign.
    30%
52. 
    WEDDING CRASHER

    As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
    1.5%
53. 
    TIL IT GOES CLICK

    Using the M60, kill 25 infected without letting go of the trigger.
    6.5%
54. 
    GRAVE ROBBER

    Collect 10 items dropped by a Fallen Survivor.
    15%
55. 
    MUTANT OVERLORD

    Play 6 Mutations.
    3.3%
56. 
    FORE!

    Knock off the heads of 18 infected with the golf club.
    12%
57. 
    KILLING THEM SWIFTLY TO THIS SONG

    Play the new Midnight Riders song on a jukebox.
    11%
58. 
    KITE LIKE A MAN

    Kill a Tank only with damage from the original Survivors.
    12%
59. 
    CACHE GRAB

    Open 5 foot lockers.
    12%
60. 
    PORT OF SCAVENGE

    Play 5 full games of Scavenge on The Port.
    1.5%
61. 
    SUPREME SACRIFICE

    Complete "The Sacrifice".
    20%
62. 
    KILL BILL

    Have Bill sacrifice himself for the team.
    14%
63. 
    BARREL ROLLED

    Kill a Special Infected with an exploding barrel.
    6.0%
64. 
    CHAOS GENERATOR

    Have all 3 generators running at once in "The Sacrifice" finale.
    6.0%
65. 
    SACRIFIZZLE

    As a Special Infected, incap someone who is trying to sacrifice themselves.
    1.5%
66. 
    STREAM CROSSER

    Survive the Cold Stream campaign on any difficulty.
    16%
67. 
    CONNECTING FIGHTS

    Play a Versus game on Dead Air from start to finish.
    3.7%
68. 
    Valve Gift Grab 2011 – L4D2

    Collect three gifts dropped by Special Infected in Versus Mode.
    6.9%
69. 
    GOOD GUY NICK

    Plays games with free weekend players and helps them survive a campaign.
    2.2%
70. 
    GHOST OF CHRISTMAS PRESENT

    Spread cheer by helping a free holiday player survive a campaign.
    10%
71. 
    GETTING STARTED

    Earn a bronze medal on any official Survival map.
    11%
72. 
    ON OUR WAY

    Earn a silver medal on any official survival map.
    5.1%
73. 
    THIS IS WHERE THE FUN BEGINS

    Earn a gold medal on any official survival map.
    3.7%
74. 
    STILL STANDING

    Survive The Last Stand campaign on any difficulty.
    12%
75. 
    THE LAST FRONTIER

    Survive The Last Stand campaign on Expert Realism.
    1.0%
76. 
    GOLDEN FREEMAN

    Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
    0.9%
77. 
    ELEPHANT IN THE ROOM

    Revive an incapacitated teammate while a Tank is nearby.
    34%
78. 
    I SPIT ON YOUR GRAVE

    As the Spitter, spit on a Survivor who is pinned by a Charger.
    5.1%
79. 
    ACID BATH

    As the Spitter, spit on a Survivor who is pinned by a Hunter.
    6.5%
80. 
    SPITFIRE

    Destroy 20 gascans as the Spitter.
    0.9%
81. 
    FLIGHT DECK

    Instantly kill a Survivor as the Charger.
    3.8%
82. 
    FAT NINJA

    As the Boomer, vomit on a Survivor without having direct line of sight with them.
    7.5%
83. 
    THREE’S A CROWD

    Rescue three Survivors from a single rescue closet.
    3.2%
84. 
    LICKETY-SPLIT

    With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
    11%
85. 
    GET SKEETED ON

    Kill a pouncing Hunter with a shotgun.
    17%
86. 
    ROCKY HORROR PICTURE THROW

    Destroy a Tank's rock in mid-air.
    16%
87. 
    SHOTGUN WEDDING

    Kill the Witch bride with a single shotgun blast on expert difficulty.
    1.2%
88. 
    ONE HIT WONDER

    As the Hunter, land a 25 damage pounce.
    1.5%
89. 
    PURE SATISFACTION

    Kill 20 Jockeys with the shovel or pitchfork.
    1.1%
90. 
    THE BIG TEN

    Survive for 10 minutes on any official map in Versus Survival.
    0.8%
91. 
    Z-GENOCIDEST 2: EPISODE 2

    Kill 53,599 infected. You made sure the dead won't rise anymore!
    2.2%
92. 
    POLE POSITION

    Escape Liberty Mall's Atrium before the first Tank appears
    3.6%
93. 
    HOUSEHOLD NAMES

    Discover the hidden room in the Last Stand campaign
    2.9%
94. 
    A LITTLE HACK AND SLASH

    Earn a bronze medal on every official survival map
    0.7%
95. 
    LIKE LAMBS TO THE SLAUGHTER

    Earn a silver medal on every official survival map.
    0.7%
96. 
    KILLING SPREE

    Earn a gold medal on every official survival map.
    0.7%
97. 
    SUPREME SURVIVALIST

    Survive for 30 minutes on any official survival map.
    1.2%
98. 
    NEW HAIRCUT

    Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
    5.4%
99. 
    THE MAIN ATTRACTION

    On the concert finale, survive until the helicopter arrives without leaving the stage
    2.2%
100. 
     THE LAST DASH

     Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
     1.0%
101. 
     GNOME ALONE

     If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.
     69%

Names, descriptions and icons are the game’s own, as Steam publishes them; the share is how many owners have unlocked each, from Steam's global figures for 101 of them.