Go to the options menu, and select the "Cheats" option. Then, press Triangle, and enter one of the following cheat code phrases to activate the corresponding cheat option. Note: Enabling a code will permanently prevent the game from being saved and trophies from being earned.List follows...
Lewis and Clark
Enter "YOU GOT YOURSELF A FINE PAIR OF EYES" as a code phrase to unlock all areas.
Invincibility
Enter "HE GIVES STRENGTH TO THE WEAK" as a code phrase.
Infinite Dead Eye
Enter "I DON'T UNDERSTAND IMNFINITY" as a code phrase.
Infinite Ammo
Enter "ABUNDANCE IS EVERYWHERE" as a code phrase.
Gun Set 1
Enter "IT'S MY CONSTITUTIONAL RIGHT" as a code phrase to unlock some weapons.
Gun Set 2
Enter "I'M AN AMERICAN. I NEED GUNS" as a code phrase to get the buffalo rifle, sawed-off shotgun, semi-auto pistol, Schofield revolver, Winchester repeater, and fire bottle x3.
Decrease Bounty
Enter "THEY SELL SOULS CHEAP HERE" as a code phrase.
Diplomatic Immunity
Enter "I WISH I WORKED FOR UNCLE SAM" as a code phrase. You will now have no bounty/wanted level.
Good Guy
Enter "IT AINT PRIDE. IT'S HONOR" as a code phrase to have a good reputation.
Famous
Enter "I AM ONE OF THEM FAMOUS FELLAS" as a code phrase to become famous.
Money
Enter "THE ROOT OF ALL EVIL, WE THANK YOU!" as a code phrase to get $500.
Coach
Enter "NOW WHO PUT THAT THERE?" as a code phrase to spawn a coach.
Horse
Enter "BEASTS AND MAN TOGETHER" as a code phrase to spawn a horse.
Infinite Horse Stamina
Enter "MAKE HAY WHILE THE SUN SHINES" as a code phrase.
Gang Chic
Enter "YOU THINK YOU TOUGH, MISTER?" as a code phrase to unlock the Treasure Hunter Outfit.
Man In Uniform
Enter "I LOVE A MAN IN UNIFORM" as a code phrase to unlock the Bureau Uniform, U.S. Army Uniform, and U.S. Marshal Uniform.
Sharp Dressed Man
Enter "DON'T YOU LOOK FINE AND DANDY" as a code phrase to unlock the Gentlemen's Suit.
Jack Attack
Enter "OH MY SON, MY BLESSED SON" as a code phrase to change John into Jack, John's son.
Who?
Enter "HUMILITY BEFORE THE LORD" as a code phrase to become a nobody.
Hic
Enter "I'M DRUNK AS A SKUNK AND TWICE AS SMELLY" as a code phrase to become drunk.
Old School
Enter "THE OLD WAYS IS THE BEST WAYS" as a code phrase to enable the Sepia filter.
Bonus weapons
Successfully complete the indicated task to unlock the corresponding weapon:
Lasso
Lasso: Obtained during the "Wild Horses, Tamped Passions" mission.
Pistols
Double-Action Revolver: Clear out the Tesoro Azul Hideout.
High Power Pistol: Obtained during the "Bear One Anotherís Burden" mission.
Lemat Revolver: For sale at the Escalera Gunsmith for $1,250 after the Revolution.
Mauser Pistol: For sale at the Blackwater Gunsmith for $800.
Schofield Revolver: Obtained during the "The Gunslingerís Tragedy" mission.
Semi-automatic Pistol: Clear out the Fort Mercer Hideout, and it will be for sale at the Escalera Gunsmith for $300.
Volcanic Pistol: Clear out the Twin Rocks Hideout, and it will then be for sale at Armadillo Gunsmith for $100.
Projectiles
Dynamite: Obtained during the "Father Abraham" mission. It will then be for sale at various stores.
Fire Bottle: Obtained during the "The Demon Drink" mission. It will then be for sale at various stores.
Throwing Knife: Obtained during the "The Great Mexican Train Robbery". It will then be for sale at various stores.
Rifles
Bolt Action Rifle: Obtained during the "The Gates of El Presidio". It will then be for sale at Escalera Gunsmith for $750.
Buffalo Rifle: Reach Master Hunter Rank 5, and it will be for sale at any Gunsmith shop for $475.
Evans Repeater: For sale at Blackwater Gunsmith.
Henry Repeater: Clear the Nosalida Hideout.
Repeater Carbine: Obtained during the "New Friends, Old Problems" mission.
Springfield Rifle: Obtained during the "We Shall Be Together in Paradise" mission, or clear the Gaptooth Breach Hideout. It will then be for sale at Thieves' Landing Gunsmith for $300.
Winchester Repeater: Clear out the Tumbleweed Hideout, or successfully complete "Spare the Rod, Spoil the Bandit" mission. It will then be for sale at Armadillo Gunsmith for $350.
Shotguns
Double-barreled Shotgun: Obtained during the "Spare the Rod, Spoil the Bandit" mission. It will then be for sale at Armadillo Gunsmith for $150.
Pump-action Shotgun: Obtained during the "And the Truth Will Set You Free" mission.
Sawed-off Shotgun: Clear Pikeís Basin Hideout. It will then be for sale at Thieves' Landing Gunsmith for $250.
Semi-auto Shotgun: For sale at Escalera Gunsmith for $1,000.
Sniper Rifles
Carcano Rifle: For sale at Blackwater Gunsmith for $1,100.
Rolling Block Rifle: Obtained during the "Empty Promises" mission.
Unlockables
Successfully complete the indicated task to unlock the corresponding bonus:
Dead Eye refills faster: Reach Sharpshooter Rank 10.
Double consumables capacity: Reach Treasure Hunter Rank 10.
Double Survivalist map duration: Reach Survivalist Rank 5.
Free stagecoaches: Reach Treasure Hunter Rank 5.
Get tonic when harvesting herbs: Reach Survivalist Rank 10.
Increased Dead Eye Level 1: Reach Master Hunter Rank 10.
Increased Dead Eye Level 2: Reach Sharpshooter Rank 5.
Increased Dead Eye Level 3: Reach Rank 10 in all Ambient challenges.
Multiplayer unlocks
Reach the indicated rank in Multiplayer mode to unlock the corresponding weapon and/or mount. Note: The Legendary mounts require you to reach level 50, and then keep playing in Legendary mode back at level 1 and reach level 50 again the indicated number of times.
Rank 1
Weapon: Cattleman Revolver, Knife
Mount: El SeÒor
Rank 2
Weapon: Repeater Carbine
Rank 3
Weapon: Throwing Knife
Rank 4
Mount: Lusitano Nag
Rank 5
Weapon: Volcanic Pistol
Rank 8
Weapon: Winchester Repeater
Mount: Turkmen
Rank 9
Weapon: Schofield Revolver
Rank 11
Weapon: Pump Action Shotgun
Mount: Cleveland Bay (Legendary 1 to 4 only)
Rank 13
Weapon: Springfield Rifle
Rank 15
Weapon: Dynamite
Mount: Hungarian Half-Bred (Legendary 2 to 4 only)
Rank 17
Weapon: Double Action Revolver
Rank 18
Weapon: Sawed-off Shotgun
Rank 20
Weapon: Rolling Block Rifle
Rank 22
Weapon: Fire Bottle
Mount: Cleveland Bay
Mount: Hungarian Half-Bred (Legendary 1 only)
Mount: American Standard-Bred (Legendary 2 to 4 only)
Rank 24
Weapon: Semi Automatic Pistol
Rank 26
Weapon: Semi Auto Shotgun
Mount: Bonzo (bull) (Legendary 3 and 4 only)
Rank 28
Weapon: Carcano Rifle
Rank 32
Weapon: Henry Repeater
Rank 33
Mount: Hungarian Half-Bred
Mount: American Standard-Bred (Legendary 1 only)
Mount: Bonzo (bull) (Legendary 2 only)
Mount: Buffalo (Legendary 3 and 4 only)
Rank 35
Weapon: High Power Pistol
Rank 37
Weapon: Double Barrel Shotgun
Mount: Albino Buffalo (Legendary 4 only)
Rank 40
Weapon: Bolt Action Rifle
Mount: American Standard Bred
Mount: Bonzo (bull) (Legendary 1 only)
Mount: Buffalo (Legendary 2 only)
Mount: Albino Buffalo (Legendary 3 only)
Rank 42
Mount: Super Bull (Legendary 4 only)
Rank 43
Weapon: Evans Repeater
Rank 46
Weapon: LeMat Revolver
Rank 49
Weapon: Mauser Pistol
Rank 50
Weapon: Buffalo Rifle
Mount: Bonzo (bull)
Mount: Buffalo (Legendary 1 only)
Mount: Albino Buffalo (Legendary 2 only)
Mount: Super Bull (Legendary 3 only)
Mount: Zebra Donkey (Legendary 4 only)