A fundamentally passive experience, unlike a whodunit should be

Rating: 6/10 (18 February 2018)

Of course, there is the matter of the source material, which couldn't have been changed significantly. However, I am here to argue that this movie was a failure for meeting none of the expectations it created.
First, as a murder mystery, it should have allowed for enough evidence for a viewer to solve the case. Instead, every time Poirot made a leap, he was using information we didn't have, that he was aware of apriori of the events in the film.
Second, there is the issue of the great cast. You expect something like this to not be much in the way of story, but that it would shine on the strength of the actors:Kenneth Branagh, Johhny Depp, Michelle Pfeiffer, Judi Dench, Willem Dafoe, Penélope Cruz and so many others. Instead, we get a bit of each, a bit theatrical, a bit over the top in some cases, even a few moments that really felt fake (although in hindsight, if the actor is playing someone who is lying, maybe they did well?), but nothing shiny. No depth of character, no emotional buildup, nothing. The absolutely best scene comes from Willem Dafoe, at the end, completely ruined by the blunt interpretation of Pfeiffer a few moments later. Branagh's obviously fake mustache had more screen time than any of the stars in that great cast.
And third, there was the story. A violent act that causes much pain is explained mostly through Poirot's description and fractured images that are supposed to make the viewer understand. Yet there is no transition from there to the present. We don't care about the event, the characters and we are completely unaware of how everything fits and how people got to this point. As a result, other than Poirot's intense stare and the nice stage sets, there is no story. I had more fun watching the introduction of the detective than in all of his solving of the train case.
Bottom line: For what it attempted, it failed at every step. For what it promised, it failed to deliver. With pain in my heart I can say that this was substandard.