IMDb classify this as horror?
Branagh must have made some major changes. I've read the original story and seen the David Suchet TV adaptation, and there's no way I'd call either even pseudo horror; they just take place around Halloween.
shareAs I understand it, the studio is only claiming that the film was INSPIRED by the book, and in reality the movie and book have little in common. The movie is basically Christie fan fiction.
I saw the film on Friday and I would say that the tag "horror-mystery" would be justifiable.