The trailer entices you with a beautiful, glamourous woman, Gal Gadot, because I think that's all the film had to offer.
The production was cheap in relative terms of film making, with few efforts to blend or disguise CGI well. Some shots were jarring, or unfocused, and added to the cheap feel.
Most actors did a good job. It was a pleasant surprise to see Russell Brand playing a character far from his own persona! However, Ali Fazal was not very subtle in the emotions he was trying to portray, Letitia Wright didn't feel like a good fit in her role, and people in the cinema burst out laughing when Armie Hammer was crying in what was meant to be one of the most serious moments of the film.
And lastly, the plot was very transparent, but of course Death on the Nile is an Agatha Christie novel, so that can't really be helped.