Halo 3 - Cheats

Unlockable: Hayabusa Armor
Collecting the three pieces of the Hayabusa Armor are collected by acquiring a certain amount of Skulls in the game. To get the Chest piece, collect six Skulls. To get the Shoulders piece, collect nine Skulls. To get the Helmet piece, collect all thirteen Skulls.

Unlockable: Katana
To unlock the Katana, which is a non-usable item that is essentially the fourth piece of Hayabusa Armor, get all thirteen Skulls in the game, and achieve a gamerscore of 1,000 (complete all achievements).

Unlockable: Bonus Content
If you complete the game on Legendary difficulty, you can grab extra content off of Xbox Live, including pictures and a making of video.

Unlockable: Special Ending
If you beat the game on Legendary mode, you will get a special, extended ending. Keep in mind that you only have to beat the final stage on Legendary mode, and not necessarily the rest of the game, in order to unlock this ending.

Unlockable: Spartan Armor Permutations
Unlock the following Spartan armor permutations by fulfilling the requirement listed…
EOD (Body) - Complete Tsavo Highway (on Legendary)
EOD (Head) - Complete the campaign mode (on Legendary)
EOD (Shoulders) - Complete The Ark (on Legendary)
EVA (Body) - Complete Tsavo Highway (on Normal, Heroic, or Legendary)
EVA (Head) - Complete the campaign mode (on Normal)
EVA (Shoulders) - Complete The Ark (on Normal, Heroic, or Legendary)
Mark V (Head) - Get the UNSC Spartan Achievement
ODST (Head) - Get the Spartan Graduate Achievement
Rogue (Head) - Get the Spartan Officer Achievement
Scout (Body) - Get the Too Close to the Sun Achievement
Scout (Head) - Get the Used Car Salesman Achievement
Scout (Shoulders) - Get the We’re in for Some Chop Achievement
Security (Head) - Get 1,000 Gamerscore Points
Security (Shoulders) - Get 750 Gamerscore Points

Unlockable: Silver Skull Locations
Blind (Located: Sierra 117)
The arms of the player and the motion tracker disappear.

Grunt Birthday Party (Located: Crow’s Nest)
If you manage to get a headshot on a Grunt, the Grunt will explode.

Unlockable: Gold Skull Locations
Black Eye (Located: Crow’s Nest)
When activated, you will have to battle enemies with melee tactics to regain shield energy.

Catch (Located: The Storm)
When activated, enemies will throw more grenades.

Famine (Located: The Ark)
When activated, dropped weapons will hold less ammunition.

Fog (Located: Floodgate)
When activated, the motion tracker disappears.

Iron (Located: Sierra 117)
When activated, you will be sent back to the beginning of the stage you’re on when you die instead of to the last checkpoint.

Mythic (Located: Halo)
When activated, all enemies will have twice as much health.

Thunderstorm (Located: The Covenant)
When activated, enemies will be of a higher rank.

Tilt (Located: Cortana)
When activated, enemies will become more resilient to your attacks.

Tough Luck (Located: Tsavo Highway)
When activated, enemies are skilled at getting away from projectiles such as grenades.