*Possible spoilers*
I think the movie was OK-ish. The acting was very well done by the whole cast. The setting was very good. The plot outline is a good teaser. However I think the movie spends too much time "insinuating" a lot, and paints its characters as weak, helpless, co-dependent, irrational, resentful. Actually, resent is the central theme to all of the characters this movie.
The problem with this breadcrumbing style is, once you figure it all out, you realize the plot wasn't complicated or intelligent at all, it was just convoluted and narrated poorly. It was done on purpose just to get you to watch to the end, whereupon I'm left with the feeling of "I wasted my life". Some say this was "haphazard" but I just think the writers were working with too much complication for the amount of running time they had.
I didn't feel like this was a thriller because most of the "thrilling" scenes were really just awkward moments that you'd be able to find in any comedy or drama movie. It's also quite obvious at the start that the GP was manipulating the characters, and you end up watching just to see if there's an interesting red-herring twist, but it all plays out quite formulaic in the end.
The main character was also weak and couldn't communicate due to being socially isolated and emotionally stupid. It was hard for me to relate to her character. I mean, I get it - stockholm syndrome, isolation and all of that, but she makes it a very tiring watch as the whole situation is just depressing and not interesting enough for me to want to follow. It's cute when she gets plucky once she has a sexual liberation, but by then she comes off as healthy as cancer. Also, the narrative paints her as a neglected, isolated, doting wife who is being psychologically and emotionally abused, which is true because her character seems to make it easy for the supporting characters to do this. We see a reincarnation when she realizes the manipulations around her, but it's hard to really care as not long before we saw her resentfully wishing her husband dead and plotting to ditch him with the suave, seductive doctor. One could see this as a "coming of age" journey, but I don't as I'm skeptical that the character has gone through enough growth to understand how much of a selfish attention-seeker she is, much less overcome it.
The weak character exception is the nurse, who I feel holds the narrative up very well. However again, due to the "insinuation" style of breadcrumbing that the narrative attempts, she even comes off as a nosy, self-righteous busy-body who neglects her job - I.E how did she not file a complaint against the GP for over-prescribing? How did she have so much time to be an investigator?? Her character could've been a little bit more impactful with a few more solo scenes (an extra 5-10 minutes?) but she definitely did not come off as unlikeable as the rest of the characters, which I realize is the point.
So, people do things where motivations aren't clear and can be taken just as negatively as they were meant positively. Everyone is manipulating each other, but not in an interesting "Game-of-Thrones" fashion, but in an uninteresting "one bad stupid character got f'ed over by an even badder stupid character" kind of way. It's hard for me to relate or to care.
In the end, the movie wasn't thrilling, it just tried really, really hard, only to fall flat on its face. But again, props to the cast for pulling the movie through the racecourse with some quality acting. Especially the GP actor who I didn't know about prior to the film - I'll be looking out for him in other roles in future.