NOTE: These are the main Halo 3 cheats that are usually applied by pressing down the right key combination. Please find the instructions on how to use these cheats below.
Cheat Codes
The following cheats can be performed during a local match or replay only. You must simultaneously PRESS & HOLD the following buttons for 3 SECONDS to toggle the effect on / off.
Click [Left Analog-stick] + click [Right Analog-stick] + [LB] + [RB] + [Down/Right] (during a local match or replay): Show coordinates
Click [Left Analog-stick] + click [Right Analog-stick] + [LB] + [RB] + [Up/Left]: Toggle panning camera
Hold [LB] + [RB] + [LT] + [A] + [Down] (during a local match or replay): Toggle weapon display
Hints
NOTE: As their name suggests hints are not exactly Halo 3 cheats, and are usually just simple (but very useful) tips on how you can unlock secret level, features, find hidden areas and such. Hopefully these will make playing Halo 3 even more entertaining.
Achievements:
Complete the following achievements to unlock Xbox Live Gamerscore points.
Landfall (20 points): Finish the first mission of the Campaign on Normal, Heroic, or Legendary.
Holdout (20 points): Finish the second mission of the Campaign on Normal, Heroic, or Legendary.
The Road (20 points): Finish the third mission of the Campaign on Normal, Heroic, or Legendary.
Assault (30 points): Finish the fourth mission of the Campaign on Normal, Heroic, or Legendary.
Cleansing (30 points): Finish the fifth mission of the Campaign on Normal, Heroic, or Legendary.
Refuge (30 points): Finish the sixth mission of the Campaign on Normal, Heroic, or Legendary.
Last Stand (40 points): Finish the seventh mission of the Campaign on Normal, Heroic, or Legendary.
The Key (40 points): Finish the eighth mission of the Campaign on Normal, Heroic, or Legendary.
Return (50 points): Finish the final mission of the Campaign on Normal, Heroic, or Legendary.
Campaign Complete: Normal (125 points): Finish the Campaign on Normal.
Campaign Complete: Heroic (125 points): Finish the Campaign on Heroic (unlocks achievement for Normal, if not earned).
Campaign Complete: Legendary (125 points): Finish the Campaign on Legendary (unlocks achievements for Normal and Heroic, if not earned).
Iron (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Black Eye (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Tough Luck (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Catch (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Fog (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Famine (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Thunderstorm (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Tilt (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Mythic (10 points): Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
Graduate (10 points): Earn 5 EXP or finish 10 games to complete the requirements for basic training (Online).
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.
Used Car Salesman (5 points): Destroy a vehicle that has three enemies in it in a ranked playlist or in campaign.
Marathon Man (40 points): Locate and access all Terminals in the 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).
Guerilla (10 points): Score over 15,000 points in the Campaign meta-game on the first mission.
Demon (10 points): Score over 15,000 points in the Campaign meta-game on the second mission.
Cavalier (10 points): Score over 15,000 points in the Campaign meta-game on the third mission.
Askar (10 points): Score over 15,000 points in the Campaign meta-game on the fourth mission.
Exterminator (10 points): Score over 15,000 points in the Campaign meta-game on the fifth mission.
Ranger (10 points): Score over 15,000 points in the Campaign meta-game on the sixth mission.
Vanguard (10 points): Score over 15,000 points in the Campaign meta-game on the seventh mission.
Orpheus (10 points): Score over 15,000 points in the Campaign meta-game on the eighth mission.
Reclaimer (10 points): Score over 15,000 points in the Campaign meta-game on the final mission.
Multiplayer Medals
If you do the following things you will get the medal while playing multiplayer. When you do the task usually it will show you by a little icon of the said medal appearing in the corner of the screen. Also at the end of each match you can check what medals you got. You can also check your overall medal count on bungie's official website. A very small amount of these are secret medals in that they don't tell you right when you get them but they will appear in your medal history. (One example of such a medal is the Steaktacular! Medal)
Assassin! Hit and kill an opponent with a melee attack from behind.
Beat Down! Hit and kill an opponent with a melee attack.
Bomb Planted! Plant the bomb in a Assault Gametype.
Bulltrue! Kill an opponent who is in the act of a sword lunge.
Death from the Grave! Kill an opponent after you have died.
Double Kill! Kill 2 opponents within 4 seconds of each other.
Extermination! Get an overkill on the opposing team, wiping out all of the members.
Flag Kill! Get a melee kill with the flag in a CTF gametype.
Flag Score! Capture the opposing team's flag in a CTF gametype.
Grenade Stick! Kill an opponent by sticking him/her with a Plasma Grenade or a Spike Grenade.
Hail to the King! Kill 5 consecutive opponents in a single life from inside the hill before it moves in a King of the Hill gametype.
Hell's Janitor! Kill 10 zombies in a row as a human without dying in an Infection gametype.
Highjacker! Board an enemy ground vehicle.
Incineration! Kill an opponent by using the Flamethrower.
Infection Spree! Kill 5 humans in a row as a zombie without dying in an Infection gametype.
Invincible! Kill 30 opponents in a row without dying.
Juggernaut Spree! Kill 5 consecutive opponents in a single run as the Juggernaut in a Juggernaut gametype.
Killapocalypse! Kill 9 opponents within 4 seconds of each other.
Killed Bomb Carrier! Kill the opposing bomb carrier in a Assault Gamtype.
Killed Flag Carrier! Kill the opposing flag carrier in a CTF gametype.
Killed Juggernaut! Kill the Juggernaut in a Juggernaut gametype.
Killed VIP! Kill the opposing VIP in a VIP Gametype.
Killimanjaro! Kill 7 opponents within 4 seconds of each other.
Killing Frenzy! Kill 10 opponents in a row without dying.
Killing Spree! Kill 5 opponents in a row without dying.
Killionaire! Kill 10 opponents within 4 seconds of each other.
Killjoy! End an opponent's killing spree—any spree.
Killtacular! Kill 5 opponents within 4 seconds of each other.
Killtastrophe! Kill 8 opponents within 4 seconds of each other.
Killtrocity! Kill 6 opponents within 4 seconds of each other.
Laser Kill! Kill an opponent by using the Spartan Laser.
Last Man Standing! Be the last human of the game in an Infection gametype.
Linktacular! Play in a matchmade game comprised of all Bungie.net users. (Secret Medal)
Mmmm Brains! Kill 10 humans in a row as a zombie without dying in an Infection gametype.
Oddball Kill! Get a melee kill when holding the ball in a Oddball gametype.
Open Season! Gun down 10 opponents with a Shotgun in a row without dying.
Overkill! Kill 4 opponents within 4 seconds of each other.
Perfection! Win a slayer game with 15+ kills without dying.
Rampage! Kill 20 opponents in a row without dying.
Running Riot Kill 15 opponents in a row without dying.
Sharpshooter! Snipe 10 opponents in a row without dying.
Shotgun Spree! Gun down 5 opponents with a Shotgun in a row without dying.
Skyjacker! Board an enemy aircraft.
Slice 'N Dice! Cut down 10 opponents with the Plasma Sword in a row without dying.
Sniper Kill! Kill an opponent by using a sniping weapon.
Sniper Spree! Snipe 5 opponents in a row without dying.
Splatter Spree! Splatter 5 opponents in a ro