Gamerscore

A Gamerpoint is an award given in a numerical value shown on your gamertag. You attain gamerpoints after completing special tasks or milestones in a game, otherwise known as achievements. In some games, gaining a certain amount of gamerpoints unlocks something in the game, such as armor or new weapons, or gaining a certain number of gamerpoints can also gain achievements in some games. While most games have 1000 gamerpoints in total, some games (eg. Xbox Live Arcade games) have far less than 1000 gamerpoints. Also, some games are not shipped with 1000 gamerpoints, but offer achievements as downloadable content. The total amount of Gamerpoints is called the "Gamerscore" by most people. Normally a game has 1000 gamerpoints but if an expansion pack is released more can be added on. The Armour Permutation Security can only be unlocked by collecting 1000 Halo 3 Gamerpoints. Other Permutations can only be achieved by completing achievements.

Note: These are not to be confused with "Microsoft Points", which are a stored-value system used for purchasing content on Xbox Live.

Campaign Achievements & Gamerpoints
Landfall - 20 points. Finish Sierra 117 from mission start on Normal, Heroic, or Legendary.

Holdout - 20 points. Finish Crow's Nest from mission start on Normal, Heroic, or Legendary.

The Road - 20 points. Finish Tsavo Highway from mission start on Normal, Heroic, or Legendary.

Assault - 30 points. Finish The Storm from mission start on Normal, Heroic, or Legendary.

Cleansing - 30 points. Finish Floodgate from mission start on Normal, Heroic, or Legendary.

Refuge - 30 points. Finish The Ark from mission start on Normal, Heroic, or Legendary.

Last Stand - 40 points. Finish The Covenant from mission start on Normal, Heroic, or Legendary.

The Key - 40 points. Finish the level Cortana from mission start on Normal, Heroic, or Legendary.

Return - 40 points. Finish the level Halo from mission start on Normal, Heroic, or Legendary.

Campaign Complete: Normal - 125 points. Complete all Campaign missions from mission start on Normal.

Campaign Complete: Heroic - 125 points. Complete all Campaign missions from mission start on Heroic (unlocks achievement for Normal, if not yet earned).

Campaign Complete: Legendary - 125 points. Complete all Campaign missions from mission start on Legendary (unlocks achievements for Normal and Heroic, if not yet earned).

Marathon Man - 40 points. Locate and access all Terminals in the Campaign.

Skull Achievements & Gamerpoints
Iron - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Black Eye - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Tough Luck - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Catch - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Fog - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Famine - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Thunderstorm - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Tilt - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Mythic - 10 points. Find and claim this skull on Normal, Heroic, or Legendary difficulty. You must begin at mission start.

Multiplayer Achievements & Gamerpoints
UNSC Spartan - 15 points. Earn your Sergeant rating to be recognized as a true Spartan Online.

Spartan Officer - 25 points. Advance to the Spartan Officer ranks Online.

Two for One - 5 points. Score a Double Kill with a single spartan laser shot in a ranked free for all playlist Online.

Too Close to the Sun - 5 points. Destroy an enemy banshee with the spartan laser or missile pod in a ranked playlist or in campaign.

Triple Kill - 5 points. Kill 3 enemies within 4 seconds of one another in a ranked free for all playlist Online.

Overkill - 5 points. Kill 4 enemies within 4 seconds of one another in a ranked free for all playlist Online.

Lee R Wilson Memorial - 5 points. Score 5 grenade sticks in any ranked free for all playlist Online.

We’re in for some Chop - 5 points. Destroy an enemy vehicle with equipment in a ranked playlist or in campaign.

Killing Frenzy - 5 points. Kill 10 enemies without dying in any ranked free for all playlist Online.

Steppin' Razor - 5 points. Score a Triple Kill with the sword in a ranked free for all playlist Online.

Mongoose Mowdown - 5 points. Splatter an enemy with the mongoose in a ranked free for all playlist Online.

Up Close and Personal - 5 points. Kill 5 enemies by melee or assassination in a ranked free for all playlist Online.

Fear the Pink Mist - 5 points. Kill 5 enemies with the needler in a ranked free for all playlist or in campaign.

Headshot Honcho - 5 points. Kill 10 enemies with headshots in a ranked free for all playlist or in campaign. If in campaign.

Used Car Salesman - 5 points. Destroy a vehicle that has three enemies in it in a ranked playlist or in campaign.

MVP - 5 points. Earn the MVP in any ranked playlist Online.

Maybe Next Time Buddy - 5 points. Board the same vehicle within 10 seconds after being boarded in any free for all playlist Online.

Meta-Game Achievements & Gamerpoints
Guerilla - 10 points. Score over 15,000 points in the Campaign meta-game on Sierra 117.

Demon - 10 points. Score over 15,000 points in the Campaign meta-game on Crow's Nest.

Cavalier - 10 points. Score over 15,000 points in the Campaign meta-game on Tsavo Highway.

Askar - 10 points. Score over 15,000 points in the Campaign meta-game on The Storm.

Exterminator - 10 points. Score over 15,000 points in the Campaign meta-game on Floodgate.

Ranger - 10 points. Score over 50,000 points in the Campaign meta-game on The Ark.

Vanguard - 10 points. Score over 50,000 points in the Campaign meta-game on The Covenant.

Orpheus - 10 points. Score over 15,000 points in the Campaign meta-game on Cortana.

Reclaimer- 10 points. Score over 15,000 points in the Campaign meta-game on Halo.