The movie is not for everyone and is a bit repetitious. However, the repetitions help build up to the ending. Admittedly I was drinking when I watched it. I was in prison some years ago and used to be tortured regularly by my cellmate (and occasionally another inmate) until I screamed. I did not really mind it and, unlike the movie, was not cut open. One time in between tortures, my cellmate had a smile on his face and I asked him, "You like this (torturing me) don't you?" He shook his head yes. Perhaps that helps explain why I liked the ending of the movie when everyone, except the victim, was beaming with glee. Besides the ending, I also liked the girl in pigtails and the marching scenes.
Review of Black Dahlia
