The tug of war
The very first image in Gone Girl, before the opening credits sequence, is Amy's head taking up the full center of the screen, before her face snaps up to look at camera and occupies all of our attention. (She is more viper than seductress here.) The first image after the credits is of a clock, dead center in the screen, indicating, among other things, that time will be important to this story, and that we're meant to be paying attention to what's at the center of the screen.
And then we see Nick for the first time, and the camera does everything it can to keep him perfectly centered against the backdrop of his suburban life. Though we opened with that shot of Amy, Fincher is telling us here that we are, instead, watching Nick's story. He is the man alone, the man who will be harassed and framed and mistreated, but also the man we are to attach ourselves to.
The first half of the film keeps treating Nick like this. In scenes where he's thrown off his game — say by the police — then one of the detectives might briefly occupy center-screen. But by and large, Nick doesn't let anyone into his territory. And the camera respects this. When Nick moves into frame from off left or off right, it usually follows him once he hits center, so he stays right there. And when he's forced to share the frame with someone — usually Amy — the shots are subtly composed so that he's closer to the center than his screen partner.

Gone Girl keeps Nick (Ben Affleck) at the center of the screen for much of the film's first half. (Twentieth Century Fox)
Gone Girl is, on many levels, a film about knowledge and about narrative control. Nick stays at the center for the film's first half, because he more or less thinks he knows everything — including his wife, including himself — and because he thinks he's in control of the narrative. Yes, he can be briefly confounded (as with the cops), but he eventually returns to his easygoing, Midwestern charm sooner or later, and the film gives him the center back.
She's taking the center, and she's only giving it back if he plays by her rules
But Fincher is also using this technique to subtly manipulate you into realizing why Amy would feel so betrayed by him. In the pages of Gillian Flynn's novel — and it must be said Flynn did exemplary work in adapting this story for the screen — Amy comes across as a collection of plot twists, more than she does an actual character. In the hands of Pike and Fincher onscreen, however, she becomes a kind of exemplar of the things women go through every day. She has her narrative taken from her first by her parents (who literally turn a better version of her into a series of books), then by her husband (who forces her to play at being someone she's not), and later by a former flame (who traps her into being yet another version of herself).
So when Nick is revealed to be cheating on her, yes, she does something completely ridiculous, but she's also sort of justified, within the film's cinematic grammar. This isn't a guy worthy of holding the screen's center. This is a bastard, just like all of those other men who refuse to cede any part of their lives to the women they supposedly love, and he deserves to pay. And more specifically, the whole rotten system deserves to pay — the men who perpetuate it and the women who prop it up. And she's just the one to start burning things.
All of this shot analysis might seem like a pointless close reading of something Fincher has done in all of his films. But Fincher has never quite used centered compositions like this. Because what he's doing is staging a literal tug-of-war for the center of the screen, and once Nick starts to realize what Amy's up to, he's already fighting a losing battle.
Because she's taking the center, and she's only giving it back if he plays by her rules.
The center holds
The central sequence that reveals that Amy faked her death is both the film's highpoint and the moment when the film turns into a true battle within the frame. Finally, Amy is situated firmly and in complete control of the screen's center, as she whips through the process of erasing her old life and beginning a new one (one that, according to her plan, will end in her death, admittedly, but it's the only way to ensure Nick pays). She drives down the highway, tossing pens out the window. She reminisces about what it took to fake her death. She stocks up on snacks, viciously tossing them into the grocery cart.
Her plan is working to perfection. She's enjoying junk food. And because Fincher has cued your subconscious so perfectly, you're ready to go along with just about anything she says, because she's just taken over the movie from a guy you increasingly can't trust. (And, indeed, in the sequences before this one, Nick has started to move ever so slightly off-center, making him feel a little more and more wrong with every millimeter lost.)
As the rest of the movie plays out, more and more of Amy's signature motifs begin to infect every frame of the film
There's been some discussion of whether this sequence loses something from the version in Flynn's book, because it directs much of Amy's rage from the men who deserve it toward the women she passes on the highway. And, to be sure, Amy doesn't think much of them or of Nick or of anyone, really. But she's also a warrior on their behalf, someone who sees that the best way to live is to tear down the walls of their own expectations. She's taking control of the movie, yes, but for the first time ever, she's also taking control of her life.
As the rest of the movie plays out, more and more of Amy's signature motifs begin to infect every frame of the film. Nick will briefly grab hold of the screen's center now and again — like when he's hired a lawyer and thinks he's on top of things — but even in a scene when he's asked by a newscaster to look directly at the camera and tell his wife what he wants to say to her, he can't quite get back to the position where he would have the most power within the film's visual narrative. The camera stops following him once he reaches center-screen. He is a man adrift, no longer the compass for us to look toward.
And Trent Reznor and Atticus Ross's score — formerly stuck only in the fabricated flashbacks from Amy's diary — begins to play throughout the rest of the film. This is Amy's reality. Everybody else is just slowly starting to realize they live in it. You can even see this in the film's use of brief nudity — it objectifies women on Nick's side, but it objectifies men once we're in Amy's world.
It's worth pointing out that Amy doesn't command the center nearly as often as she might like. She's thrown off by a few flaws in her plan that leave her imprisoned by a former lover. But every time she launches a new scheme, every time she spins a new story, every time she tells a new lie, every time she gains more knowledge, she moves closer and closer to commanding that center entirely. She is turning the tricks of the movie against it. She is turning the lies of her husband against him. And she is taking back the center of the screen for women everywhere. She was made to be the supporting character in somebody else's story, but now, she's going to be the protagonist. She doesn't care if you like it.
The last time Nick occupies screen center is in a scene where he's finally acquiesced to Amy's plan, agreed to live with her and raise the child she conceived without even sleeping with him (thanks to an old sperm donation). She sits off to the side gratefully this time, because she's annexed the whole damn movie, and she can afford to be gracious. And the last image we see? Amy's face in close-up again. We're on the other side of the mirror.
A truer self
As mentioned above, Fincher doesn't have the world's greatest track record when it comes to feminist filmmaking. So why this film? Why this character? The answer here may be simple: is it so hard to believe that a director famous for being a perfectionist, for endless takes of scenes and exquisitely composed shots, might identify with a woman who doesn't like her life and decides to completely knock it to the ground, so she might build a completely new one in which she micro-manages every little thing? And why wouldn't the director of Fight Club — a very good film about American masculinity — not similarly be interested in a film about the constrictive roles placed on women in our society, the parts they are asked to play?
But even if Gone Girl is just sort of accidentally feminist, so what? The film is a bracing corrective to years of thrillers on screens both big and small that reduce their female characters to victims designed to die because they were the wrong kind of woman, or married the wrong kind of man (which was completely their fault, of course). They are bait, or objects to be protected, not characters in their own right. And even when these movies try to turn their female characters into something more, they tend to fetishize those characters' suffering — as, ironically, happened in Fincher's own Girl With the Dragon Tattoo. But Gone Girl is different. It takes a character who would just be a corpse in so many other stories and turns the entire movie over to her.
Even if Gone Girl is just sort of accidentally feminist, so what?
The women in Gone Girl, like the women in too many movies, have had their agency taken, have been stripped of their power, by their husbands, or by their boyfriends, or by their parents, or by the system, or just by the horrible turns a life can take. But Amy refuses to accept this. She pushes back toward the center, and she takes what's hers.
For this reason, I find the ending of Gone Girl strangely hopeful — and I assure you you are perfectly fine to find this reading very strange. Nick is finally able to see Amy not as an image he's projecting onto her, but as the person she actually is, the person she's always been. She might be a monster, but he knows her in his "marrow," and there's something poetic, gorgeous, in the notion of knowing all of the worst things about a person but still settling in beside them and smiling for the camera, telling the lie they need you to tell, that the world might believe them someone better.
I doubt Amy would see it this way, though. Amy, I think, would laugh at this reading. Because in the end, what she's reduced Nick to is the character so many women are asked to play in movies just like this — the supportive spouse, who sits by his wife's side and smiles and says all the right things and never once gets to be anything but what she says he is. That, to her, might not feel like hope. It would, I suspect, feel more like justice.