There are eleven different cheats to be unlocked in Manhunt, usually to make the otherwise challenging game easier or simply for fun.
Conditions
To unlock cheats, most of which you have to complete scenes for with at least 3 stars, but for a few codes you must finish the game on Hardcore difficulty with 5 stars in every level (as Fetish only gives up to 4 stars). The codes will appear on the Art Panels as you complete each 2 consecutive scenes, split into two parts each for one cheat. To turn them on once unlocked, enter the full codes at the title screen. If you enter them correctly, you will be notified by the Painkiller sound effect (except for God Mode, which is silent).
These codes can only be used after you complete 2 consecutive scenes with a 5 star ranking. The only way to achieve a 5 star ranking is by beating missions on Hardcore.
Also, you cannot save while cheating.
Note that cheats will not work in the four bonus scenes. The reason why is unknown.
The code effects are:
God Mode: Cash becomes invulnerable to damage. However, he can still be disoriented by being shot from a Tranquilizer Rifle. The health meter also becomes red (this only occurs in the PC release, as the PS2/Xbox versions remain green).
Runner: Cash's stamina meter becomes infinite, allowing him to run non-stop and easily evade Hunters.
Silence: Suppresses all sounds made by Cash, making sneaking to perform executions much easier.
Invisibility: Enemies will no longer spot Cash in the open. Note the code does not mean Cash is actually invisible; Hunters still chase and attack him when alerted, and the Tramp/Journalist will continue as normal.
Regenerate: Cash will gradually regain lost health over time like Stamina (but at a relatively slower pace). Like its counterpart, he will recover slightly faster if he is standing still.
Fully Equipped: Cash will automatically and usually be armed with a certain weapon of every Class from within the level to allow the player to gain an advantage against Hunters, and if it is a firearm, it will have maximum ammunition (except for any guns requiring over 100 rounds such as the Nail Gun, Assault Rifle or Sub-Machine Gun). A few scenes will make Cash have weapons unavailable or cut from said level.
Super Punch: Cash's fist attacks (and up-close blows with weapons) will kill enemies instantly, except for the Cerberus Leader (who requires two hits) and Piggsy (who is invincible except for executions).
Helium Hunters: All Hunters' voices are comically sped up to simulate being in helium gas, and will explode and die instantly (but won't be dismembered from the blast) anytime they take damage, similar to Gasoline Cans/Canisters. Cash and the Tramp/Journalist are also affected, and with the exception of Cash himself (who still takes normal damage), will indeed explode when hit. If groups of enemies are close together and one is killed, a domino effect chain reaction can be seen. Executions will continue as normal. Note that explosions will potentially kill the player at close range, so it is not recommended to use this code in scenes where melee weapons are required in combat. The cheat's name is somewhat of a misnomer during gameplay, as helium, like nitrogen, is actually a non-flammable gas and therefore not combustible; This means Hunters blowing up upon impact strongly implies they are also being in hydrogen or other highly explosive natural gases such as methane or carbon monoxide.
Rabbit Skin: Replaces Cash's model with that of the White Rabbit. It does not affect gameplay or the storyline.
Monkey Skin: Replaces Cash's model with the Monkey costume seen in Monkey See, Monkey Die. It does not affect gameplay or the storyline.
Piggsy Skin: Replaces Cash's model with that of Piggsy. It does not affect gameplay or the storyline.
PlayStation 2
These codes are all for the PS2 version of the game.
Runner: R2, R2, L1, R2, Left, Right, Left, Right (Scenes 01 and 02)
Silence: R1, L1, R2, L1, Right, Left, Left, Left (Scenes 03 and 04)
Regenerate: R2, Right, Circle, R2, L2, Down, Circle, Left (Scenes 05 and 06)
Helium Hunters: R1, R1, Triangle, Circle, Square, L2, L1, Down (Scenes 07 and 08)
Fully Equipped: R1, R2, L1, L2, Down, Up, Left, Up (Scenes 09 and 10)
Super Punch: L1, Triangle, Triangle, Triangle, Circle, Circle, Circle, R1 (Scenes 11 and 12)
Rabbit Skin: Left, R1, R1, Triangle, R1, R1, Square, L1 (Scenes 13 and 14)
Monkey Skin: Square, Square, R2, Down, Triangle, Square, Circle, Down (Scenes 15 and 16)
Invisibility: Square, Square, Square, Down, Square, Down, Circle, Up (Scenes 17 and 18)
Piggsy Skin: Up, Down, Left, Left, R1, R2, L1, L1 (Scenes 19 and 20)
God Mode: Down, Down, Circle, Up, Square, Triangle, Square, R2, Up, Up, L1, Triangle (After you finish the game on Fetish or Hardcore difficulty)
PC
These codes are all for the PC version of the game.
Runner: URUNFAST (Scenes 01 and 02)
Silence: ALLRDEAF (Scenes 03 and 04)
Regenerate: HEALBACK (Scenes 05 and 06)
Helium Hunters: THEYBOOM (Scenes 07 and 08)
Fully Equipped: UGOTARMS (Scenes 09 and 10)
Super Punch: UHITHARD (Scenes 11 and 12)
Rabbit Skin: BUNYSUIT (Scenes 13 and 14)
Monkey Skin: HELLSUIT (Scenes 15 and 16)
Invisibility: EVILEYES (Scenes 17 and 18)
Piggsy Skin: PIGGSUIT (Scenes 19 and 20)
God Mode: IMINVINCIBLE (After you finish the game on Fetish or Hardcore difficulty)
Disable Cheats: CHEAT OFF
Xbox
These codes are for the Xbox version of the game.
Runner: White, White, L Trigger, White, Left, Right, Left, Right (Scenes 01 and 02)
Silence: R Trigger, L Trigger, White, L Trigger, Right, Left, Left, Left (Scenes 03 and 04)
Regenerate: White, Right, B, White, Black, Down, B, Left (Scenes 05 and 06)
Helium Hunters: R Trigger, R Trigger, Y, B, X, Black, L Trigger, Down (Scenes 07 and 08)
Fully Equipped: R Trigger, White, L Trigger, Black, Down, Up, Left, Up (Scenes 09 and 10)
Super Punch: L Trigger, Y, Y, Y, B, B, B, R Trigger (Scenes 11 and 12)
Rabbit Skin: Left, R Trigger, R Trigger, Y, R Trigger, R Trigger, X, L Trigger (Scenes 13 and 14)
Monkey Skin: X, X, White, Down, Y, X, B, Down (Scenes 15 and 16)
Invisibility: X, X, X, Down, X, Down, B, Up (Scenes 17 and 18)
Piggsy Skin: Up, Down, Left, Left, R Trigger, White, L Trigger, L Trigger (Scenes 19 and 20)
God Mode: Down, Down, B, Up, X, Y, X, White, Up, Up, L, Y (After you finish the game on Fetish or Hardcore difficulty)