Oni Target Practice: Complete the game on a normal setting to unlock oni target practice. Character must use guns or arrows to pick off Genma eggs that go by on tracks.

Adventures of Heihachi: Complete the game on a normal setting to unlock this short storyline featuring Heihachi.

Oni Training: Complete every training session and beat the game to unlock this bonus training session.

Genma Puzzle Space: Solve every Puzzle Treasure Box in the game and complete the game to unlock this mini-game.
Samanosuke's Warlords Weapons
To unlock the three weapons that Samanosuke wielded in Onimusha: Warlords obtain the Fire Seal, the Thunder Seal and the Wind Seal and complete the game. The next time the game is played through the three weapons reappear in the alleyway where Samanosuke materializes in the present time period.
Panda Suit Photo Opportunity
In the Bolougne Zoo, just outside of the building with the air-sealed door, there is a wooden photo shoot prop. Stand behind it and the camera shows your character in the panda suit from Onimusha Warlords, with Ako as the baby panda.