Halo: Reach Xbox 360 Cheats

Lone Wolf bonus mission
Successfully complete the game on the Normal difficulty or higher to play the Lone Wolf bonus mission after the credits end.
Haunted Helmet Purchase every single helmet and helmet permutation to unlock a bonus helmet called the "Haunted Helmet". It is a helmet with an open visor that shows your character's face as a skull.
Special nameplates Successfully complete the indicated task to unlock the corresponding nameplate for Multiplayer mode. To activate it, log into Bungie.net, select "Account", "Game Settings", then "Nameplates".

Assault rifle: Played the Halo: Reach beta in May 2010.
Bungie: Activate blue flames through the Bungie Mobile iPhone/iPod app.
Designated Marksman Rifle (DMR): Subscribe to the Bungie Pro hosting service.
HALO: Unlock the original Halo logo, Halo 2 logo, and Halo 3 logo nameplates.
Halo 2 logo: Played Halo 2 on Xbox Live before April 15, 2010.
Halo 3 logo: Play any campaign level in Halo 3 on Xbox Live.
Marathon Durandal symbol: Have Marathon Durandal in your recently played games list, and login at Bungie.net.
MJOLNIR Mk VI helmet logo: Unlock any four of the Halo PC, Halo 2, Halo 3, Halo 3: ODST, or Halo: Reach beta nameplates.
ODST logo: Play Halo 3: ODST on Xbox Live.
Original Halo logo: Register your Halo PC product code at Bungie.net.
Star: Activate through the Bungie Mobile iPhone/iPod app.
The Septagon symbol: Join Bungie.net, and login with your Gamertag's email address.

Invincibility and permanent Armor Lock This trick requires two players. Enter Forge mode, create an Armor Lock ability, then drop it on player two. Next, create another Armor Lock ability and press B. Then, go to delete all of these from the map. Click it, and hover over "Yes". Have player two go into Armor Lock. While they are in Armor Lock, select "Yes" at the "Delete all of these from map" message. Player two will now be invincible, and can move around in permanent Armor Lock. You can still use other equipment, such as Evade.
Faster melee attacks Press RB, then quickly press X + RB.
Lower your weapon While in a local game, click the Right Analog-stick and hold Down + [Reload] + [Grenade Switch].
Auto fire While holding an automatic weapon, crouch and press Select for the gun to fire repeatedly.
Auto fast forward in Theater mode Hold RT, press Start, release RT, then press Start again to automatically fast forward your replay until you pause it or press RT.