Speed Reader
25Complete the level “The Library” on Legendary difficulty in 30 minutes or less.
Unlocked: 24 Jan 2012 23:19:13
Complete the level “The Library” on Heroic difficulty or higher without dying.
Unlocked: 22 Jan 2012 13:51:22
Complete the level “Two Betrayals” on Heroic difficulty or higher without killing any Grunts.
Unlocked: 08 Jan 2012 16:32:19
Headhunter
50Locate all the skulls hidden throughout the campaign.
Unlocked: 07 Jan 2012 03:18:04
The Maw
25Complete the level “The Maw” on any difficulty.
Unlocked: 07 Jan 2012 01:49:21
Complete every level of the game on Normal difficulty.
Unlocked: 07 Jan 2012 01:49:21
Complete every level of the game on Heroic difficulty.
Unlocked: 07 Jan 2012 01:49:21
Complete every level of the game on Legendary difficulty.
Unlocked: 07 Jan 2012 01:49:21
This Side Up
10Complete the Warthog ride on the level “The Maw” without being forcibly ejected from your vehicle.
Unlocked: 07 Jan 2012 01:46:25
Escape “The Maw” on Legendary with at least a minute left on the count down.
Unlocked: 07 Jan 2012 01:46:25
Read all of the terminals hidden throughout the campaign.
Unlocked: 07 Jan 2012 00:51:37
Keyes
25Complete the level “Keyes” on any difficulty.
Unlocked: 07 Jan 2012 00:31:26
Kill every Elite on the level “Keyes” on Heroic difficulty or above.
Unlocked: 07 Jan 2012 00:31:11
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25Kill 100 Flood Infection Forms on the level “Keyes” on Heroic difficulty or above.
Unlocked: 06 Jan 2012 23:17:29
Complete the level “Two Betrayals” on any difficulty.
Unlocked: 06 Jan 2012 23:09:51
Complete the level “Two Betrayals” on Legendary difficulty without picking up a new weapon.
Unlocked: 06 Jan 2012 23:09:51
The Library
25Complete the level “The Library” on any difficulty.
Unlocked: 03 Jan 2012 19:35:04
Locate half of the skulls hidden throughout the campaign.
Unlocked: 03 Jan 2012 19:00:53
Escape the Forerunner facility on the level “343 Guilty Spark” in 21 minutes or less.
Unlocked: 03 Jan 2012 18:35:50
Complete the level “343 Guilty Spark” on any difficulty.
Unlocked: 03 Jan 2012 18:22:46
Kill 50 Flood Combat Forms on the level “343 Guilty Spark” on Heroic difficulty or higher.
Unlocked: 03 Jan 2012 18:20:36
Complete the level “Assault on the Control Room” on any difficulty.
Unlocked: 03 Jan 2012 02:31:42
Read half the terminals hidden throughout the campaign.
Unlocked: 03 Jan 2012 02:16:18
Pilot a Banshee on the level “Assault on the Control Room.”
Unlocked: 03 Jan 2012 02:15:54
Destroy four Wraith tanks in “Assault on the Control Room” with the Scorpion tank, in a single play.
Unlocked: 03 Jan 2012 01:43:04
Complete the level “The Silent Cartographer” on any difficulty.
Unlocked: 03 Jan 2012 01:06:58
Grenadier
25Escape the map room in “The Silent Cartographer” without firing a shot on Heroic or Legendary.
Unlocked: 03 Jan 2012 01:06:58
Beachhead
10Storm the beach of “The Silent Cartographer” with no marine casualties on Heroic or Legendary.
Unlocked: 02 Jan 2012 23:57:53
Tsantsa
50Complete any level with at least three skulls active on Heroic difficulty or higher.
Unlocked: 29 Dec 2011 02:36:56
Complete the level “Truth and Reconciliation” with at least four rounds left in your Sniper Rifle.
Unlocked: 28 Dec 2011 22:40:05
Complete the level “Truth and Reconciliation” on any difficulty.
Unlocked: 28 Dec 2011 22:01:49
Kill all the enemies in the first encounter of “Truth and Reconciliation” without being detected.
Unlocked: 28 Dec 2011 20:50:44
No-Fly Zone
10Destroy three of the four Banshees on “Halo” on any difficulty during a single play-through.
Unlocked: 26 Dec 2011 03:29:51
Halo
25Complete the level “Halo” on any difficulty.
Unlocked: 26 Dec 2011 03:10:40
Complete any level on Normal difficulty cooperatively.
Unlocked: 26 Dec 2011 03:10:40
Brovershield
20Complete any level on Heroic difficulty cooperatively.
Unlocked: 26 Dec 2011 03:10:40
Bro Hammer
50Complete any level on Legendary difficulty cooperatively.
Unlocked: 26 Dec 2011 03:10:40
Complete the level “Halo” on any difficulty without entering a vehicle.
Unlocked: 26 Dec 2011 03:10:40
Complete any level on Heroic difficulty or higher without taking health damage.
Unlocked: 26 Dec 2011 01:52:11
Complete the level “Pillar of Autumn” on Legendary without picking up an Overshield.
Unlocked: 26 Dec 2011 01:32:05
Walk it Off
25Complete the level “Pillar of Autumn” on Legendary without picking up a health kit.
Unlocked: 26 Dec 2011 01:32:05
Find your first campaign skull.
Unlocked: 26 Dec 2011 01:16:15
Complete the level “Pillar of Autumn” on any difficulty.
Unlocked: 26 Dec 2011 01:10:23
Read a terminal.
Unlocked: 26 Dec 2011 00:47:21