Natural Selection 2

1. 
   Combat Engineer

   Build 10 Extractors in a single round
   0.9%
2. 
   The Doctor is In

   Weld your teammates 10 times in a single round
   6.9%
3. 
   First Class Post

   Use a Phase Gate
   16%
4. 
   Mood Lighting

   Weld a Power Node
   14%
5. 
   Repairman

   Weld 5 Power Nodes in a single round
   5.3%
6. 
   They Just Keep Coming

   Kill a Skulk
   19%
7. 
   Economic Sabotage

   Kill a Gorge
   13%
8. 
   Air Defense

   Kill a Lerk
   13%
9. 
   Asymmetrical Combat

   Kill a Fade
   11%
10. 
    Big Game Hunter

    Kill an Onos
    9.8%
11. 
    Strategic Thinking

    Follow 5 Commander’s orders in a single round
    17%
12. 
    Security Detail

    Kill an Alien while defending an Extractor
    14%
13. 
    Long Term Investments

    Kill an Alien while defending an Extractor 5 times in a single round
    3.2%
14. 
    Adam Smith

    Kill an Alien while defending an Extractor 10 times in a single round
    0.8%
15. 
    Economics 101

    Kill an Harvester
    15%
16. 
    Dambuster

    Kill 5 Harvesters in a single round
    2.5%
17. 
    No Tech For You

    Kill 10 Harvesters in a single round
    0.7%
18. 
    Tag!

    Parasite a Marine
    16%
19. 
    I See Human Scum

    Parasite 10 Marines in a single round
    5.3%
20. 
    Wall Hacks!

    Parasite 20 Marines in a single round
    2.2%
21. 
    Team Player

    Destroy an Extractor
    13%
22. 
    Barking Dog

    Destroy 5 Extractors in a single round
    2.4%
23. 
    Rifles Only

    Destroy 10 Extractors in a single round
    0.6%
24. 
    Cultivation

    Build a Hive as Gorge
    4.1%
25. 
    Disarmament

    Kill a Marine who has a Shotgun
    12%
26. 
    Firefighter

    Kill a Marine who has a Flamethrower
    11%
27. 
    Bomb Defusal

    Kill a Marine who has a Grenade Launcher
    9.3%
28. 
    You're Walking Now

    Destroy an Exosuit
    7.4%
29. 
    Slimy

    Use a Kharaa Tunnel
    14%
30. 
    Battle Ready

    Evolve one Kharaa Upgrade
    14%
31. 
    Unfair Advantage

    Evolve three Alien upgrades
    10%
32. 
    They Came From Behind

    Kill a Marine after sneaking as Skulk
    9.6%
33. 
    Most Valued Xenomorph

    Kill a Marine while defending a Harvester
    9.3%
34. 
    Secure Investments

    Kill a Marine while defending a Harvester 5 times in a single round
    0.9%
35. 
    Patron Saint of Res

    Kill a Marine while defending a Harvester 10 times in a single round
    0.4%
36. 
    Protip

    Kill a Marine with two Bites and a Parasite
    4.0%
37. 
    Untouchable

    Kill a Marine while having full health
    16%
38. 
    Demolitions

    Deal 7500 structure damage in a single round
    16%
39. 
    Bloodrage

    Deal 4000 player damage in a single round
    15%
40. 
    Checkmate

    Deal the killing blow to a Hive or Command Station
    9.6%
41. 
    ‘Tis But a Scratch

    Get healed with a single health point
    12%
42. 
    Quality Assurance

    Kill a developer
    1.5%
43. 
    Unsportsmanlike Conduct

    Taunt after killing an enemy player
    3.2%
44. 
    Regicide

    Kill the enemy team's Commander
    6.6%
45. 
    No More Fancy Toys

    Destroy 100 resources worth of enemy technology in a single round
    11%
46. 
    Burning Cash

    Destroy 200 resources worth of enemy technology in a single round
    6.4%
47. 
    Recession

    Destroy 300 resources worth of enemy technology in a single round
    3.9%
48. 
    First Adventure

    Complete both tutorials.
    16%
49. 
    Explorer

    Use Play Now
    15%
50. 
    TSF

    Play a round as a Marine
    18%
51. 
    Kharaa

    Play a round as an Alien
    17%
52. 
    Traveler

    Play on 3 different maps
    16%
53. 
    Eat Your Greens

    Complete all new player missions
    8.3%
54. 
    Darwin Award

    Too determined to listen to good advice.
    0.5%
55. 
    Terminal Velocity Facepalm

    For when a regular facepalm doesn't cut it...
    0.5%
56. 
    New Recruit

    Complete the Marine tutorial.
    14%
57. 
    Fresh Larva

    Complete the Alien tutorial.
    13%
58. 
    Unleashed

    Rattling the Cage reaps its own reward
    2.2%
59. 
    Arcade Champion

    Spent some time playing arcade game modes
    1.9%
60. 
    Old Recruit

    Complete the Marine Commander tutorial.
    6.2%
61. 
    Clogbeard's TreasureSecret

    Steam withholds the description of a secret achievement.
    0.4%
62. 
    Trust No-one

    I don't know what's in there, but it's weird and pissed off, whatever it is.
    0.4%
63. 
    It came from...behind

    Infest everybody and stay alive.
    0.5%
64. 
    Sgt. MacReady

    Be the last and only survivor against the Infestation
    0.3%
65. 
    Higher Lifeform

    Complete the Alien Commander tutorial.
    4.5%
66. 
    The Last Straw

    Gorges can only take so much...
    0.4%
67. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
68. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
69. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
70. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
71. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
72. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
73. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
74. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
75. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
76. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
77. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
78. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
79. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
80. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
81. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
82. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
83. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
84. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
85. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
86. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
87. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
88. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
89. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
90. 
    Matched Play Commander UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
91. 
    Matched Play Commander UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
92. 
    Matched Play Commander UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
93. 
    Matched Play Commander UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
94. 
    Matched Play Commander UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
95. 
    Speed Demon

    Complete the Skulk Race Challenge
    1.3%
96. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
97. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
98. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
99. 
    Matched Play UnlockSecret

    Steam withholds the description of a secret achievement.
    0.0%
100. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
101. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
102. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
103. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
104. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
105. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
106. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
107. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
108. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
109. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
110. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
111. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
112. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
113. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
114. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
115. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
116. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
117. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
118. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
119. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
120. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
121. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
122. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
123. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
124. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
125. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
126. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
127. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
128. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
129. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
130. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
131. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
132. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
133. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
134. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
135. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
136. 
     Matched Play Commander UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%
137. 
     Matched Play UnlockSecret

     Steam withholds the description of a secret achievement.
     0.0%

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 137 of them.