A Haunting in Venice is the third film in the now Poirot trilogy directed and starring Kenneth Branagh. I'm a very casual Poirot viewer. My only exposure to the character is through these films and the British tv series, which I watched long ago and barely remember. As someone who has never read a Poirot novel, I personally liked the previous two films by Branagh, Murder on the Orient Express and Death on the Nile. I know many Agatha Christie fans do not, and I can understand why given that these films are not extremely loyal to the source material from what I'm told, especially this film.
I haven't read the novel, A Halloween Party, but I'm told the only thing this film has in common with it is that it takes place on Halloween, and that there is a Halloween party in it. The culprit is the same in both, but the motivation and victims are entirely different. I'm guessing Branagh went with a far more obscure Poirot story this time, banking on the fact that not many have read and so they won't notice the many alterations made to it.
However, as someone who is only a casual fan, just like with the last two films, I'll be judging this solely as a standalone piece and not an adaptation. From that viewpoint, I think the movie is good. Like with the last two movies, the film looks great, is wonderfully shot. This one evokes a strong haunting, Halloween atmosphere. The acting is good by everyone involved, even the child actors.
The film is also significantly shorter than the previous two, though in some ways to the film's detriment. I felt Poirot solved the mystery a bit too quickly. The pacing is a bit rushed at the end, and I'm not entirely convinced of how Poirot comes to the conclusions he does.
Despite that, the film is a fun mystery/haunting story. A fun movie to watch, especially around Halloween. I would still say I still like Murder on the Orient Express the most. But I would put this film slightly above Death on the Nile. If you're someone who likes the previous to films in this series, there's no reason not to check this out.