"I'm the cunt you married. The only time you liked yourself was when you were trying to be someone this cunt might like. I'm not a quitter, I'm that cunt. I killed for you; who else can say that? You think you'd be happy with a nice Midwestern girl? No way, baby! I'm it."
Admittedly, I haven't read the book. But seeing this was made infinitely more entertaining by going to the theater with Riley, who has. (And also with two friends, one of whom was also in the same boat as yours truly.) So two people present knew what to expect, and I, naturally, knew nothing at all. But that's fine, as seeing it sparked an interest in me to read the novel, which is probably all part of Gillian Flynn's grand money-making scheme.
Now, some parts are rather predictable. I soon figured out that Ben Affleck's character, Nick, was being framed for his wife's disappearance / murder. That essentially drives the plot for the first half of the film. But something kind of interesting happens during the back half. We're given a huge perspective shift and finally discover a bit about Amy and her motivations as a character, including just how wickedly cunning and manipulative she can be. It's an interesting commentary on the expectations we have for women and the sexism inherent in how we view their desires and behavior.
The first part of the film drags a bit and seems strangely forced, hammy, and inauthentic. But the latter half changes the game entirely and in a fresh, unexpected way. I was understandably surprised at first, because there's loads of talent in this movie ranging from Meryl Streep to Rosamund Pike (the lead actress and title character). But it's absolutely worth sticking through the initial parts of the movie. The beauty is that it's all carefully constructed in such a way as to highlight the brutal, unflinching punch of feminist-misogynist duality in later developments. Rosamund's portrayal of Amy is nothing short of masterful in her chilling emotional disturbance. I've heard that the novel treats Amy as more of a balanced, complex character rather than largely a "crazy bitch", but it's fascinating either way. I'm actually rather looking forward to finding out for myself.