Finishing the story of Onimusha: Way of the Sword isn't the end. Not only will you gain access to New Game+, but you'll also unlock a new difficulty level, as is tradition in the series. This time, it's the fearsome Carnage Mode.
Carnage Mode becomes available after completing the game for the first time on either Story or Action difficulty. You can then start a new game or New Game+, choose your difficulty again and select Carnage Mode.
In Carnage, enemies and bosses are far more aggressive and deal significantly more damage. It's essentially a major step up in difficulty, but this isn't the classic Critical Mode where Issen attacks were effectively your only reliable way to deal damage. Think of it as the game's ultimate difficulty setting.
As you complete missions and defeat bosses on Carnage, you can unlock new Haori Coat appearances, Outfits and Sword Appearances. Carnage is also required if you want to earn every trophy or achievement in the game, as completing the story on this difficulty unlocks the True Onimusha trophy/achievement.
