Escape “The Maw” on Legendary with at least a minute left on the count down.
Unlocked: 17 Nov 2011 20:56:19
Complete the level “Two Betrayals” on Heroic difficulty or higher without killing any Grunts.
Unlocked: 17 Nov 2011 17:19:36
Speed Reader
25Complete the level “The Library” on Legendary difficulty in 30 minutes or less.
Unlocked: 17 Nov 2011 16:46:19
Complete the level “Two Betrayals” on Legendary difficulty without picking up a new weapon.
Unlocked: 17 Nov 2011 14:55:39
Complete the level “The Library” on Heroic difficulty or higher without dying.
Unlocked: 17 Nov 2011 13:44:11
Grenadier
25Escape the map room in “The Silent Cartographer” without firing a shot on Heroic or Legendary.
Unlocked: 17 Nov 2011 12:46:18
Beachhead
10Storm the beach of “The Silent Cartographer” with no marine casualties on Heroic or Legendary.
Unlocked: 17 Nov 2011 12:24:31
Destroy four Wraith tanks in “Assault on the Control Room” with the Scorpion tank, in a single play.
Unlocked: 17 Nov 2011 12:10:28
Complete the level “Truth and Reconciliation” with at least four rounds left in your Sniper Rifle.
Unlocked: 17 Nov 2011 11:26:15
Kill all the enemies in the first encounter of “Truth and Reconciliation” without being detected.
Unlocked: 17 Nov 2011 11:05:03
Complete the level “Halo” on any difficulty without entering a vehicle.
Unlocked: 17 Nov 2011 10:03:49
No-Fly Zone
10Destroy three of the four Banshees on “Halo” on any difficulty during a single play-through.
Unlocked: 17 Nov 2011 09:57:01
Complete every level of the game on Legendary difficulty.
Unlocked: 16 Nov 2011 21:25:23
Complete every level of the game on Heroic difficulty.
Unlocked: 16 Nov 2011 21:25:22
Complete every level of the game on Normal difficulty.
Unlocked: 16 Nov 2011 21:25:21
The Maw
25Complete the level “The Maw” on any difficulty.
Unlocked: 16 Nov 2011 21:25:19
This Side Up
10Complete the Warthog ride on the level “The Maw” without being forcibly ejected from your vehicle.
Unlocked: 16 Nov 2011 21:22:27
Headhunter
50Locate all the skulls hidden throughout the campaign.
Unlocked: 16 Nov 2011 21:07:10
Read all of the terminals hidden throughout the campaign.
Unlocked: 16 Nov 2011 20:19:53
Keyes
25Complete the level “Keyes” on any difficulty.
Unlocked: 16 Nov 2011 20:05:24
Kill every Elite on the level “Keyes” on Heroic difficulty or above.
Unlocked: 16 Nov 2011 20:05:06
Popcorn.gif
25Kill 100 Flood Infection Forms on the level “Keyes” on Heroic difficulty or above.
Unlocked: 16 Nov 2011 19:29:21
Complete the level “Two Betrayals” on any difficulty.
Unlocked: 16 Nov 2011 18:07:08
The Library
25Complete the level “The Library” on any difficulty.
Unlocked: 16 Nov 2011 17:03:22
Kill 50 Flood Combat Forms on the level “343 Guilty Spark” on Heroic difficulty or higher.
Unlocked: 16 Nov 2011 16:07:46
Escape the Forerunner facility on the level “343 Guilty Spark” in 21 minutes or less.
Unlocked: 16 Nov 2011 15:50:02
Complete the level “343 Guilty Spark” on any difficulty.
Unlocked: 16 Nov 2011 15:05:45
Complete the level “Assault on the Control Room” on any difficulty.
Unlocked: 16 Nov 2011 14:30:11
Tsantsa
50Complete any level with at least three skulls active on Heroic difficulty or higher.
Unlocked: 16 Nov 2011 14:30:09
Read half the terminals hidden throughout the campaign.
Unlocked: 16 Nov 2011 14:22:50
Pilot a Banshee on the level “Assault on the Control Room.”
Unlocked: 16 Nov 2011 14:11:01
Locate half of the skulls hidden throughout the campaign.
Unlocked: 16 Nov 2011 13:09:55
Complete the level “The Silent Cartographer” on any difficulty.
Unlocked: 15 Nov 2011 20:14:41
Complete the level “Truth and Reconciliation” on any difficulty.
Unlocked: 15 Nov 2011 19:21:00
Halo
25Complete the level “Halo” on any difficulty.
Unlocked: 15 Nov 2011 17:34:00
Complete any level on Normal difficulty cooperatively.
Unlocked: 15 Nov 2011 10:58:08
Brovershield
20Complete any level on Heroic difficulty cooperatively.
Unlocked: 15 Nov 2011 10:58:03
Bro Hammer
50Complete any level on Legendary difficulty cooperatively.
Unlocked: 15 Nov 2011 10:58:02
Walk it Off
25Complete the level “Pillar of Autumn” on Legendary without picking up a health kit.
Unlocked: 15 Nov 2011 10:58:00
Complete the level “Pillar of Autumn” on Legendary without picking up an Overshield.
Unlocked: 15 Nov 2011 10:57:58
Complete any level on Heroic difficulty or higher without taking health damage.
Unlocked: 15 Nov 2011 10:57:57
Find your first campaign skull.
Unlocked: 14 Nov 2011 13:11:14
Complete the level “Pillar of Autumn” on any difficulty.
Unlocked: 14 Nov 2011 13:07:58
Read a terminal.
Unlocked: 14 Nov 2011 12:49:13