Alternate costumes:
Successfully complete the game under the hard difficulty
setting to unlock Samanosuke's alternate costume.
Successfully complete the game with an S rank by getting
all of the Fluorites to unlock Kaede's alternate costume.
Speed trial mini-game:
Collect over 20 Fluorites (blue rocks) during game play.
Complete and save the game. The Onimusha Spirits speed trial
mini-game will be unlocked. Successfully complete the mini-game
to unlock the "Ultimate mode" option, which allows the game to
be played with the Bishamon Sword, unlimited ammunition,
99 Soul Absorbers, and automatic magic regeneration.
Easy mode:
Start a game and die about five times under the normal difficulty
setting. After enough deaths, a message will appear, stating that
a new easy mode is open. Note: You cannot achieve an S rank when
playing in easy mode.
Difficult mode:
Successfully complete the game with a time under three hours.
Ultimate mode:
Successfully complete the game under the hard difficulty setting
with any rank except for S. Alternately, successfully complete the
Onimusha Spirits mini-game.
X rank:
Successfully complete the game in difficult mode without using the
Bishamon Sword, get and wear the Ogre Armor, and collect all of
the Fluorites.
Sites: