Death on the Nile is an old-fashioned murder mystery, lavishly filmed in wonderful locations, on a beautiful vintage pleasure craft (of course it isn't vintage to the early 20th century passengers), and peopled by top-of-their-game stars and character actors. And Branagh being Branagh, a little art creeps in, as well... mostly in the form of the ghosts of the past that frequently trouble master detective Hercule Poirot. Though many of the passengers on the sumptuous cruise along the Nile have their own ghosts and demons, too, also artfully and subtly conveyed.
The murder mystery itself is very clever, suitably complex but also playing fair. You can figure it out if you pay attention and have the imagination to fill in the blanks. Myself, I got halfway there: my suspicions went in the right direction but I couldn't figure out the mechanics of the crime. But that's okay, I enjoyed it when Poirot explained it all to me, which I'm sure was Mr. Branagh's intention.