Overkill
5Kill 4 enemies within 4 seconds of one another in a ranked free for all playlist (Online).
Unlocked: 10 May 2009 03:57:30
Splatter an enemy with the mongoose in a ranked free for all playlist (Online).
Unlocked: 15 Nov 2008 21:30:14
Board the same vehicle within 10 seconds after being boarded in any free for all playlist (Online).
Unlocked: 15 Nov 2008 17:55:35
Score 5 grenade sticks in any ranked free for all playlist (Online).
Unlocked: 15 Nov 2008 08:10:41
Score a Triple Kill with the sword in a ranked free for all playlist (Online).
Unlocked: 09 Nov 2008 21:43:30
Advance to the Spartan Officer ranks (Online).
Unlocked: 01 Nov 2008 03:36:59
Kill 3 enemies within 4 seconds of one another in a ranked free for all playlist (Online).
Unlocked: 31 Oct 2008 21:35:02
Kill 10 enemies without dying in any ranked free for all playlist (Online).
Unlocked: 31 Oct 2008 20:29:23
Finish the Campaign on Legendary (unlocks achievements for Normal and Heroic, if not earned).
Unlocked: 30 Oct 2008 04:48:56
Last Stand
40Finish the seventh mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: 10 Oct 2008 23:44:35
Thunderstorm
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: 10 Oct 2008 22:42:04
Destroy an enemy banshee with the spartan laser or missile pod in a ranked playlist or in campaign.
Unlocked: 10 Oct 2008 22:20:15
Refuge
30Finish the sixth mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: 10 Oct 2008 00:30:58
Famine
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: 09 Oct 2008 23:24:34
Cleansing
30Finish the fifth mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: 09 Oct 2008 00:04:49
MVP
5Earn the MVP in any ranked playlist (Online).
Unlocked: 08 Oct 2008 00:06:55
Fog
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: 07 Oct 2008 04:03:29
Assault
30Finish the fourth mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: 07 Oct 2008 04:00:02
Catch
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: 07 Oct 2008 03:26:59
Score a Double Kill with a single spartan laser shot in a ranked free for all playlist (Online).
Unlocked: 05 Oct 2008 21:35:37
The Road
20Finish the third mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: 01 Oct 2008 21:33:31
Tough Luck
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: 01 Oct 2008 21:06:17
Kill 5 enemies by melee or assassination in a ranked free for all playlist (Online).
Unlocked: 30 Sep 2008 23:29:24
UNSC Spartan
15Earn your Sergeant rating to be recognized as a true Spartan (Online).
Unlocked: 28 Sep 2008 00:52:59
Graduate
10Earn 5 EXP or finish 10 games to complete the requirements for basic training (Online).
Unlocked: 27 Sep 2008 18:28:59
Landfall
20Finish the first mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: Offline
Holdout
20Finish the second mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: Offline
The Key
40Finish the eighth mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: Offline
Return
50Finish the final mission of the Campaign on Normal, Heroic, or Legendary.
Unlocked: Offline
Finish the Campaign on Normal.
Unlocked: Offline
Finish the Campaign on Heroic (unlocks achievement for Normal, if not earned).
Unlocked: Offline
Iron
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: Offline
Black Eye
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: Offline
Tilt
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: Offline
Mythic
10Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Unlocked: Offline
Destroy an enemy vehicle with equipment in a ranked playlist or in campaign.
Unlocked: Offline
Kill 5 enemies with the needler in a ranked free for all playlist or in campaign.
Unlocked: Offline
Kill 10 enemies with headshots in a ranked free for all playlist or in campaign.
Unlocked: Offline
Destroy a vehicle that has three enemies in it in a ranked playlist or in campaign.
Unlocked: Offline
Marathon Man
40Locate and access all Terminals in the Campaign.
Unlocked: Offline
Guerilla
10Score over 15,000 points in the Campaign meta-game on the first mission.
Unlocked: Offline
Demon
10Score over 15,000 points in the Campaign meta-game on the second mission.
Unlocked: Offline
Cavalier
10Score over 15,000 points in the Campaign meta-game on the third mission.
Unlocked: Offline
Askar
10Score over 15,000 points in the Campaign meta-game on the fourth mission.
Unlocked: Offline
Exterminator
10Score over 15,000 points in the Campaign meta-game on the fifth mission.
Unlocked: Offline
Ranger
10Score over 50,000 points in the Campaign meta-game on the sixth mission.
Unlocked: Offline
Vanguard
10Score over 50,000 points in the Campaign meta-game on the seventh mission.
Unlocked: Offline
Orpheus
10Score over 15,000 points in the Campaign meta-game on the eighth mission.
Unlocked: Offline
Reclaimer
10Score over 15,000 points in the Campaign meta-game on the final mission.
Unlocked: Offline
On a Legendary map, get a Splatter Spree during any ranked or social match.
Unlocked: 29 Mar 2009 04:16:55
Road Rage
25On a Legendary map, get 5 Warthog chaingun kills during any ranked or social match.
Unlocked: 28 Mar 2009 23:40:12
Defend This
50On a Legendary map, get a flag melee kill during any ranked or social match.
Unlocked: 27 Mar 2009 23:03:28
On a Legendary map, get 3 Oddball melee kills during any ranked or social match.
Unlocked: 23 Jan 2009 04:16:20
On a Legendary map, get two Double Kills during any ranked or social match.
Unlocked: 08 Nov 2008 21:11:08
Flag Dropped
25On a Legendary map, get 2 flag carrier kills during any ranked or social match.
Unlocked: 08 Nov 2008 20:48:31
On a Legendary map, get 3 assassinations during any ranked or social match.
Unlocked: 08 Nov 2008 01:28:24
On a Mythic map, get a Perfection medal during any ranked or social match.
Unlocked: 26 Jun 2009 23:37:47
On a Mythic map, kill 2 Zombies during any ranked or social match.
Unlocked: 23 May 2009 02:26:56
On a Mythic map, infect 2 humans during any ranked or social match.
Unlocked: 17 May 2009 03:55:45
On a Mythic map, get an Extermination during any ranked or social match.
Unlocked: 25 Apr 2009 08:10:32
Killtacular
25On a Mythic map, get a Killtacular during any ranked or social match.
Unlocked: 14 Apr 2009 03:10:54
Post Mortem
25On Orbital, get 2 Death From the Grave medals during any ranked or social match.
Unlocked: 13 Apr 2009 22:00:00
Hammer Time
25On Assembly, get 5 Hammer kills during any ranked or social match.
Unlocked: 12 Apr 2009 22:19:46
On a Mythic map, get a Bulltrue medal during any ranked or social match.
Unlocked: 11 Apr 2009 22:32:40
On a Mythic map, get a Killjoy medal during any ranked or social match.
Unlocked: 11 Apr 2009 21:51:03
Tank Dropper
25On any Mythic map, get a kill on another player while in monitor mode.
Unlocked: 11 Apr 2009 21:41:34
On Orbital, find the hidden skull.
Unlocked: 11 Apr 2009 21:31:17
On Assembly, find the hidden skull.
Unlocked: 10 Apr 2009 22:04:38
On Sandbox, find the hidden skull.
Unlocked: 10 Apr 2009 22:01:53
On Heretic, get a Sword Spree during any ranked or social match.
Unlocked: 09 Nov 2009 04:56:53
Pull
25On Citadel, get a Shotgun Spree during any ranked or social match.
Unlocked: 01 Oct 2009 05:35:14
Ghost Patrol
25On Longshore, get 3 kills with a Ghost during any ranked or social match.
Unlocked: 30 Sep 2009 23:55:02
On Citadel, find the hidden skull.
Unlocked: 23 Sep 2009 01:27:57
On Longshore, find the hidden skull.
Unlocked: 23 Sep 2009 01:12:35
On Heretic, find the hidden skull.
Unlocked: 23 Sep 2009 01:10:36
Find all the hidden skulls on the Mythic maps.
Unlocked: 23 Sep 2009 01:27:57
After 9/25/08, complete Halo on 4-player Legendary LIVE co-op, with Iron, and everyone in Ghosts.
Unlocked: 03 May 2009 21:55:23
Get to the rank of Lieutenant in any playlist in the new EXP progression system.
Unlocked: 01 Nov 2008 03:36:59
Enter into any ranked or social playlist with 7 EXP on the 7th of the month.
Unlocked: 07 Oct 2008 23:39:47