I've been playing more Onechanbara but having a lot of trouble. I eventually got to a point where I had to give up and re-start the game on Easy difficulty. The game seems to have kind of expected me to do that from the beginning because you're characters strength carries over and is independent of which difficulty or level you're playing. So even though normal difficulty starts off pretty breezy, it becomes sort of painful. And it never feels like the difficulty comes from having a certain level of skill.
Easy seems much better, possibly because I'm overpowered, but now the bosses seem like simple pushovers rather than the slogs they were before. This game's sword mechanics are all from the "hack and slash or whatever" school of game design. It's fun enough, but it's also kind of bad without being a really interesting kind of bad.