Some players came away from Onimusha's demo worried that the game would be too easy, a concern I've addressed in-depth based on my own time with the game. The good news is that I think the challenge level is well-judged for most people, and Onimusha does have a hard mode.
For those who hoped to jump right into the hardest possible difficulty from the main menu, though, I've got some bad news: you're going to have to beat the game first.