Let a teammate spawn on you 5 times in an Invasion Matchmaking game.
Scored 50,000 points in a Firefight game.
Scored 15,000 points in Score Attack Firefight Matchmaking.
Earned a First Strike Medal in a Matchmaking game.
Earned a Killing Spree in multiplayer Matchmaking.
Advanced a Commendation to a Silver state.
Completed a Weekly Challenge.
Completed the 10th mission on Normal or harder.
Completed the Campaign on Heroic difficulty.
Completed the Campaign on Normal difficulty.
Completed the 9th mission on Normal or harder.
Completed the 8th mission on Normal or harder.
Killed 3 of the anti-aircraft batteries during the 8th mission.
Completed the 7th mission on Normal or harder.
Completed the 6th mission on Normal or harder.
Destroyed the Corvette's engines & escort in under 3 minutes in the 6th mission on Heroic or harder.
Completed the 5th mission on Normal or harder.
Killed the Elite Zealot before he escaped during the 5th mission.
Recommended a file to someone.
Used the File Browser to upload a file to your File Share.
Completed the 4th mission on Normal or harder.
Performed an Assassination on an enemy.
Reached the rank of Corporal in the UNSC.
Cleared the 2nd mission without setting foot in a drivable vehicle.
Killed 7 Moa during the 2nd mission of the Campaign.
Completed the 3rd mission on Normal or harder.
Traded weapons with an AI ally in Campaign.
Completed the 2nd mission on Normal or harder.
Killed 10 enemies in a Firefight or Campaign session with the DMR.
Used a Health Pack to replenish life after taking body damage.
Killed 10 enemies in a Firefight or Campaign session with the M6G pistol.
Purchased an item from the Armory.
Earned a Killionaire medal in Firefight.
Completed a Firefight set on Legendary without dying.
Scored 200,000 points in a Firefight game.
Scored 1,000,000 points in a Firefight game.
Completed all of the Daily Challenges in a given day.
Reached the rank of Captain in the UNSC.
Purchased an item from the Armory that required the rank of Lt. Colonel.
Defiant: Returned two flags in a matchmade CTF game.
Noble 1: Earned a Double Kill from the Grave in multiplayer Matchmaking.
Noble 1: Earned a Double Kill with the shotgun in multiplayer Matchmaking.
Defiant: Killed 3 players with the Oddball in a matchmade Oddball game.
Noble 1: Killed a player at long range with the DMR in a matchmade Slayer game.
Noble 1: Your team collected all of the flags in a matchmade Stockpile game.
Defiant: Captured two flags from an enemy capture zone in a matchmade Stockpile game.
Noble 1: Your team blew up the research facility in a matchmade Invasion game on Breakpoint.
Noble 1: Destroyed a vehicle using Armor Lock in a matchmade game.
Noble 1: Earned a kill in a matchmade Rocket Race game.
Defiant: Prevented the attacking team from touching the flag in a matchmade 1-Flag CTF game.
Defiant: Assassinated a player that just exited Armor-Lock in a matchmade game.
Defiant: Was the last surviving uninfected player in a matchmade Infection game.
Anniversary: Earned 3 headshots in a row in a matchmade game.
Anniversary: Infected 3 players in a single round in a matchmade Infection game.
Anniversary: Killed the flag carrier with a Plasma Grenade in a matchmade game.
Anniversary: Performed a Beat Down on an enemy while using the Jetpack during a matchmade game.
Anniversary: Ran over 5 people with a vehicle in a matchmade game.
Anniversary: Captured 10 skulls at once in a matchmade Headhunter game.
Anniversary: Killed an enemy with their own grenade that was stuck to you in a matchmade game.
Completed every mission in Halo: Reach alone, on Legendary.
Completed the Campaign on Legendary difficulty.
Killed 2 vehicles at once with the Target Locator during the 3rd mission.
Killed 10 enemies in Firefight or Campaign with a supercombine explosion.
Earned a Triple Kill while Jetpacking in Campaign, Firefight or Matchmaking.
Finished the 9th mission on Legendary with the Scorpion intact.
Hijacked a Banshee during the Reach Campaign.
Performed an Assassination against an Elite to survive a fall that would've been fatal.
Won a game of Invasion in the 1st phase.
As an Elite, killed 5 Spartan players in Matchmaking.
