Cheats
Unlike other games in the series, Red Dead Revolver doesn't feature any enterable cheats, however they can be unlocked in "Bounty Hunter" mode after completing the story.
Red Dead Revolver's cheats are unlocked by successfully completing challenges on specific levels during "Bounty Hunter" mode. You'll unlock this mode once you complete the game for the first time. It allows you to replay specific levels in any order, where completing them and passing the challenge objective will reward a cheat.
Once cheats have been unlocked, they can be activated from the pause menu. Enabling cheats does not disable trophies or achievements and there is no penalty for using them, meaning you'll essentially unlock the ability to make the game easier once you earn them.
Cheats can be used in the single player story or Bounty Hunter mode, but can't be enabled in Showdown Mode (local multiplayer). Using cheats in Bounty Hunter mode will make additional challenges easier to complete.
Unlocking cheats will unlock them for all "player profiles", so starting a new game with a new player profile would provide access to any unlocked cheats from a different profile.
Unlockable Cheats
Sad Stars
Whenever blood would be displayed, either when you shoot an enemy, or an enemy shoots you, a shower of colored stars with sad faces appears instead of the blood.
How To Unlock
In Bounty Hunter Mode on the mission "The Mine", you must pass the mission in under 3 minutes.

No HUD
All 2D graphical elements are removed from the heads-up display on screen. This includes ammo, health, dead eye and money displays, as well as weapon crosshairs and dead eye lock-on targets.
How To Unlock
In Bounty Hunter Mode on the mission "Stagecoach", you must kill at least 40 enemies and pass the mission.

Bite The Bullet
All bullets deal a signficantly increased amount of damage. If you're hit by enemy bullets, you'll lose almost all of your health and will usually die in 2 hits. Most enemies will die in a single shot and bosses will take increased damage from each bullet.
How To Unlock
In Bounty Hunter Mode on the mission "Fort Diego", you must earn a combo of at least $300 and pass the mission.

No Distortion
All "camera distortion" is removed from the gameplay, meaning the graphics displayed are much sharper.
How To Unlock
In Bounty Hunter Mode on the mission "End Of The Line", you must get a combo of over $200 and pass the mission.

Infinite Dead Eye
Your Dead Eye meter will not decrease after use, meaning it can be repeatedly used without the need to refill it.
How To Unlock
In Bounty Hunter Mode on the mission "Battle Finale", you must kill all of the pedestrians in one minute. The time limit starts when Kelley gets back up and begins his rampage.

Golden Gun
All bullets you fire will deal a signficantly increased amount of damage. Most enemies will die in a single shot and bosses will take increased damage from each bullet. Enemy bullets are not affected and will continue to deal normal damage.
How To Unlock
In Bounty Hunter Mode on the mission "Siege", you must pass the mission while keeping Jack Swift's health bar above 50%.

Invincibility
Your health bar will not decrease when being hit by enemy weapons, meaning you cannot be killed.
How To Unlock
In Bounty Hunter Mode on the mission "Fall From Grace", you must pass the mission in under 1 minute.

Cheat Unlock Tips
Invincibility is by far the best cheat to unlock and will help massively with all of the other objectives thoughout the game. As a result, you should play "Fall From Grace" in Bounty Hunter mode as soon as possible. Once Invincibility has been unlocked, you should consider replaying "Siege" to unlock Golden Gun then "Battle Finale" to unlock Infinite Dead Eye. Those three cheats will make the rest of the challenges a breeze.
"No Name" Secret Cheat
When creating a new player profile, you're asked to enter your player name. If you clear the name and enter only a single space (represented by the ">" on the keyboard interface), then click on "End", the game will set your name as "Rstar".
Doing this will set a random selection of store items throughout the game to be considered already purchased, giving you a head start in the game.
The items which are pre-purchased will vary and can include weapons and upgrades, health and dead eye increases, journal pages and showdown characters, plus showdown stages.