Before seeing a preview of this superhero superclash, reviewers were advised multiple times - by email, verbally, and in including an introduction video by director Zack Snyder - not to put spoilers out into world.
So be warned. This review may contain some things you didn't already know about this movie because that is what reviews are meant to do.
And yes, go to Batman v Superman: Dawn of Justice, prepared to be surprised by stuff that isn't already in the trailer.
But also be prepared to have one's enthusiasm for yet another superhero movie tested by a film that takes itself very seriously and - but for maybe two jokes - isn't out to entertain.
As well as that personal plea, Snyder has employed another clever anti-spoiler tactic.
He's delivered a movie where it's frequently hard to figure what the heck is going on anyway.
At some points, watching BvS:DoJ felt like the reels or digital projection files were out of order. Either that or some sort of clever anti-spoiler narrative-scrambling device had kicked in.
There's a point where suddenly Batman and Superman and various henchmen confront each other in a sequence that's got nothing to do with anything that's happened in the movie to that point.
It just sort of arrives an hour or so into the movie, as if from a parallel world - something that happens in the endlessly rebooting world of superhero comics, but at least they tend to print those tangential storylines in different issues.
But no, it's a dream sequence (or is it?). And it's not the only one delivering moments which play like stupid tricks while adding to the general bamboozlement.
No, superhero movies aren't meant to be paragons of narrative logic.
BvS:DoJ starts off promisingly, focusing on Ben Affleck's refreshingly engaging take on Bruce Wayne and Batman - though his voice has the furball problem that Christian Bale had - before the movie starts veering in and out of various mad muddles.
Yes it is frequently visually spectacular, especially in the IMAX edition. Though Snyder's overwrought screen and sound design can make you miss the real-world clarity and relative coherence of Christopher Nolan's
After recapping the much-told story of Batman's genesis, it begins with a different view of the final events of its predecessor, Snyder's 2013 movie Man of Steel. That film copped some flak for how Superman's showdown with fellow Kryptonian, General Zod, rained destruction on Metropolis. Which wasn't a good look for a supposed saviour of mankind.
Turns out that backlash was part of the plan all along - Bruce Wayne witnessed the 9/11-like devastation from below, including to the building which housed Wayne Enterprises.
As Wayne later tells reporter Clark Kent at a bash thrown by Lex Luthor: "We have a bad history with bullies dressed like clowns."
Kent, on the other hand, thinks The Daily Planet should be looking into the vigilante disguised as a Bat in Gotham, the city across the bay.
Then along comes young Lex Luthor, seemingly angry that he's the smartest guy in any room but powerless despite his very big brain. He has a fiendish plan to pit the two against each other so he can ... um. Not sure actually.
As Luthor, Jesse Eisenberg is an odd disappointment. He's obviously been told to amp up the geek-snark he displayed as Mark Zuckerberg in The Social Network but his verbosity makes him more annoying than villainous. DC Comics, and especially Batman, always had the best baddies. But Luthor and his Dr Frankenstein act is a weak spot.
But it is Batman v Superman and the film does offer an impressively high-decibel answer on that old playground question: Who would win in a fight?
The movie takes a rather long time to get to that. Maybe the reason it's also called Dawn of Justice is because it feels like it takes all night.
Yes this is also the prelude to upcoming DC Justice League movies which is why Wonder Woman (Gal Gadot) turns up fashionably late and there are mentions of The Flash, Aquaman and Cyborg.
That sure makes for an overstuffed movie. It also has to get in Lois Lane (Amy Adams) repeatedly being rescued by her high-flying boyfriend, Holly Hunter as a senator pondering Superman oversight in Washington DC, Martha Kent being wisely maternal and a scene where the late Jonathan Kent (Kevin Costner) turns up to tell his adopted son to build a baseball diamond in a cornfield ... or something.
There is also a monster. It's possibly the product of Weta Digital's involvement because it sure looks like there's some Middle-earth Balrog/Orc/Troll DNA in his big ugly pixels.
Yes Affleck's good, Cavill fills out his suit prettily enough and when the two are going chin-to-chin, dimple-to-dimple, it makes for a mighty clash of the titans. It's just the movie they get to do that in is more batty than super.
Movie: Batman v Superman: Dawn of Justice
Cast: Ben Affleck, Henry Cavill, Jesse Eisenberg, Jeremy Irons
Director: Zack Snyder
Running time: 151 mins
Verdict: Big on making biff. Small on making sense.