What are we to make of the gender codes in Batman v Superman? Is it confused or certain, modern or prehistoric? To reach a clear conclusion, I might have to tell you the end, or at least flesh out my analysis that the lasso in the final battle is a metaphor for the omnipotent but non-lethal vagina. How do you like my spoiler huh? HUH?

Everyone knows how to adjudicate the sexism in a normal film: do the women have agency, or are they perpetually needing rescue? Are the women naked more often than the men, for no clear reason? Does it pass the Bechdel test – do two women have a conversation in a film about something other than a man? (This criterion is met so rarely now that it’s pretty much the definition of arthouse.)

In a world where things are always catching fire, who can say how much nudity is acceptable?

In the more likely event that the women talk about nothing but men, is their dialogue at all sophisticated, or – going by their words alone – could they be any age from five? Upon these foundations, you can begin to adjudicate the film as you would a person, weigh it up for sleaziness, slut-shaming, the whole busy toolkit by which women are undermined; although then you get into the territory of “does the film think that, or just the character, and is misogyny actually conceived as a slur on that character in order that he might ‘go on a journey’?” The distinction is incredibly easy to make in real life, but could happily take Twitter 20,000 years.

The motifs of the superhero film complicate this slightly: nobody really talks about anything but good and evil; everybody’s clothes are so tight that they all may as well be naked. In a world where things are always catching fire for no reason, even your eyeballs, who can really say how much nudity is practical and how much titillating? Yet in the respects that Batman v Superman differs from the norm, it has quite a lot to say, albeit not all of it egalitarian or hugely consistent.

If Bond can do it … Superman joins Lois Lane in the bath. Photograph: Supplied by Warner Bros

Lois Lane is your classic spunky heroine, quick with the self-believing backchat, very slow in the matter of staying alive without constant assistance. Here she is in the desert, interviewing a terrorist, who unaccountably offered safe passage to a reporter from a seemingly local newspaper without knowing anything about her. “They didn’t tell me you were a lady,” says the terrorist, to which she shoots back, “I’m not a lady, I’m a journalist.” There’s a set of journalistic tropes which subvert the damsel in distress norm (broadly: critical thinking, tenacity and boldness). If we take survival as the main aim of any sensible person, these traits don’t help, but they’re a start, right?

On the matter of nudity, Lane has her main emotional journey while in the bath – don’t we all? Then Superman gets into the bath, fully clothed, to cheer her up, which is a new cinematic shorthand for “evolved man who sees you as an equal” (cf Daniel Craig in Casino Royale – the significance is that he is macho enough not to care about his clothes getting wet even if they’re leather, while feminine enough to see that a supportive gesture is required. It’s genius, really.)

Lynda Carter in the 1970s TV series Wonder Woman Photograph: Alamy

Lois isn’t woeful, but breaks no moulds in terms of what she brings to the narrative; her sex appeal is built around peril, and her intimacy is in her helplessness. The headline act is Wonder Woman (we’ll come to the maternal ideal later; it will be much later, and will only take a second, because it is pretty basic). Her only skill, for a long time, is in managing to steal something from Batman which he left in a perfectly visible place where any of us could have stolen it. “You know it’s true what they say about little boys,” she tells him, “born with no natural inclination to share. I didn’t steal it, I borrowed it.”

Weirdly, people actually don’t say that about little boys. Babies of both genders are shown to have a sense of fairness, from which sharing naturally proceeds, from the age of about six months. I baulk anyway at having to go through this phase of “women [superheroes] are innately better” before you get to a place where you acknowledge that essentialism has all been a giant delusion.

In the future, it seems, women will still need men for IT support

Besides the stealing/borrowing, she has a show-stopping cleavage, unleashed to maximum effect in a series of asymmetrical clothes whose only internal logic is to make sure you can see her breasts but her neck is covered (otherwise it all goes a bit Bet Lynch). Furthermore, the stolen/borrowed files are no good to her, since she is foxed by the encryption, while Batman cracks into them with no problem at all, a plot element that has literally no purpose except to underscore that, even in the distant future, when you don’t need shelves put up because you no longer read books, women will still need men for IT support.

As we approach the final battle, her power is completely unknown, seeded by nothing except a photograph. From this standing start, she joins the fight with an urgent yet unhurried mien, in a spirit of cooperation rather than bashing the boys’ heads together (which would have been patronising to a walk-outable degree). She retains an ability to process information: “[this gigantic demon] seems to feed on energy”. The military men on the ground figured this out already, probably with computers, but her behaviour nonetheless registers in stark contrast with that of Batman and Superman who, once engaged in battle, can’t think about anything and can barely keep their pointy ears on straight.

Gal Gadot as Diana Prince (Wonder Woman’s alter ego) in Batman v Superman Photograph: Clay Enos/LFI/Photoshot

She does not launch the decisive attack. She is not the first among equals. Her weapon, at the climactic moment, is the lasso, just a holding device. It bothers me that if we do buy this as a metaphor for the female pudenda – as I think we must – then her gender becomes her status. There is no way for the female superhero to be anything but a wingman or helpmeet, in this framing. No monster died from not being able to use his arms. Yet I’ll take, in consolation, the change in her costume; the star-spangled pants have gone, the all-American colour-scheme has been muted into a kind of elemental Celtic mud.

Compared to every Wonder Woman in history, she has a brute force; and set against Batman and Superman, she is the least kitsch, which may on some elemental level *MASSIVE SPOILER ALERT* account for her survival.

One final note on the mothers: in the most preposterous plot twist, Batman and Superman, geared up for the whole film for an epic war in which personal animus mingles with a wider collision over their different interpretations of a superhero’s quiddity, manage to come together because their mothers are both called Martha. A kind of Kray twins sentimentality mixed with a nerd’s love of banal coincidence, this is about the least feminist updating of anything ever. Plainly, it will take more than Wonder Woman to smash the patriarchy, but she’s a start.