I saw this movie with no idea of the plot. I just read some people online telling that it was a good movie by well loved director Takashi MIke. I like many movies that he did. And I had expectation. And well the movie is not a horror, it is not scary. Does it have blood? Yes. Crazy people? Yes. Is it funny and entertaining? Well not that much. Here is where the issue is for me. When the movie finish I thought "is this all?" that Meh feeling. No real drama or tension or big surprise. Everything move in a smooth way, And as somebody else already wrote, yes very good opening scene, and then you think, ok ok something good will come.
I have no idea of the book or comic this is based on. So maybe the story was all already there with not so much room to change things.