I’m not sure how I felt about the changed ending. It was more a movie style ending. Having the gardener in it was pointless as they used none of his parts from the book.
Maybe I’m just not a nice person but my issue with both book and film is why Nina would ever go back and help Millie, knowing she’d be risking her life to do so, especially as she has a child and worked so hard to get away. My attitude would be “you wanted my husband, now you have him”. Although the book explains it a little better than the film did.
That said, it was entertaining enough. Me and DD had both read the book so that’s why we went to see it.