I already read Before I Go To Sleep so I already knew what the ending was. The interest in going to see this film was to see the what way they adapted the book into film.
Actors wise I think they did a good job in choosing Nicole Kidman, Colin Firth and Mark Strong. Stand out was probably Colin as he had so many characters in there. From caring husband to somebody who might not trust. Mark Strong aswell did the same in a smaller scale.
In the film instead of writing a diary the main character Christine does a daily video diary on a camera that she has to hide from her husband.I found this hard to believe because not only that she have to find a spot to secretly record her video clips but she had to watch them back again in the morning. It seemed super risky for somebody who didn’t trust her husband.
Apart from that I think the mystery was well executed and it maintained the thrilleresque and tense moments throughout the film.