Maybe its because I've read the manga that I didn't like this movie that much, but the beginning was promising and I had hope for it but it fumbled at the middle and end.
The plot deviates from the manga but its still the same thing. Hideo is still the same but Hiromi doesn't do anything for the movie, you could have removed her from the movie and nothing will have changed. In general characters lack development and its hard to get invested in them. The ending is bad, we don't really understand what will happen to the characters, in particular what is with Hiromi.
Read the manga you will not regret it but the movie its just another bad Japanese live action.