Cheat Mode:
Play through the game in bounty hunter mode to unlock various cheats, including "Invincibility", "Infinite Deadeye", "Golden Gun" (one hit kills), "Bite the Bullet", "Sad Stars", "No HUD", "No Distortion", "Show Player Position", "Show AI Info", and "Big Money".

Bounty Hunter / Hard Mode:
You must complete the game to unlock Bounty Hunter and Hard Mode.

Red Wood Revolver / Very Hard Mode:
Complete the game on hard mode.

All showdown characters and journal pages: 
Buy every item. 

Invincibility: 
Complete the bounty hunter goal on Fall from Grace. 

Completion Bonuses:
Successfully complete the game to unlock bounty hunter mode and hard mode.