Unless you have read the manga, you'll be quite loss in this movie as I have. I felt that the movie had many critical flaws. First, the movie was too short. As a result there was no time for characterization and plot development was rushed. Also I think that people who did not read the manga first would be lost.
Some people criticize the fact that the story is very dark.
I feel that the story is dark no matter how you look at it and a flowery backdrop to this story would be an injustice. One thing that really annoyed me was the way the whole situation between Seishiro and Subaru was handled. For people like myself who are big fans of Tokyo Babylon this was a huge let down. However the movie does have its strong points. As you watch this movie, if nothing else, it's worth it just to see the beautiful artwork.