Strongest equipment mode: 
Complete the game on the hard difficulty setting. Then, 
start new game to begin with strong equipment.

Mind twister mode: 
Complete the game with all 18 artworks to unlock mind 
twister mode.

Hard mode: 
Complete the game on the normal difficulty setting to unlock
the hard difficulty setting.

Kick ass mode:
Complete the game on the hard difficulty setting to unlock 
the kick ass difficulty setting.

Ending bonuses: 
Complete the game to unlock the Scenario Route option, 
Man In Black Suit mini-game, and Team Onimusha mode; 
as well as a FMV preview of Onimusha 3.

Critical mode: 
Complete Team Onimusha mode to unlock critical mode.