Building on the foundations laid in Man of Steel and Batman v Superman: Dawn of Justice, this is a four-hour epic that sweeps its audience up and carries you along, whether through tightly-scripted character beats or frenetic, supercharged fight sequences.
Gone is the element of "heroic cruelty" that rather tainted the previous two films, this is pure, old fashioned, comic book action, served in a modern, celebratory, style.
Having sworn a pledge on Superman's grave, Bruce Wayne aka Batman (Ben Affleck) teams up with Diana Prince aka Wonder Woman (Gal Gadot) to hunt down fellow metahumans and form an alliance against the coming darkness foretold by Lex Luthor (Jesse Eisenberg).
Eventually they build a team consisting of Victor Stone aka Cyborg (Ray Fisher), Arthur Curry aka Aquaman (Jason Momoa), and Barry Allen aka The Flash (Ezra Miller), to face down the alien warlord Steppenwolf (Ciarán Hinds), who is preparing the Earth for the arrival of Darkseid (voiced by Ray Porter), the definitive uber-bad guy in DC Comics.
I don't want to dwell too much on the previous, theatrical, iteration of Justice League, as reshaped by the disgraced Joss Whedon, when he took over the project after Zack Snyder had to step away due to a dreadful family tragedy.
However, if you have seen that then you will recognise certain scenes and moments in this new cut, but so much of it is new - to us - material that was shelved for the version that was released four years ago.
The general thrust of the story is similar, but better developed, explored, and explained now that it's in the hands of its original creator.
All the characters come across as more three-dimensional, and Cyborg has been elevated from an almost incidental player back to the heart of the story, as Zack and scriptwriter Chris Terrio envisaged him.
Cyborg has been on my radar for as long as I've been collecting comics, as he was a founding member of the Marv Wolfman/George Perez era of the New Teen Titans, which transformed me from a dabbler in comics to a full-on collector and addict.
I have to be honest, though, until this movie, I'd never found him that interesting a character, but Zack (and Chris) - and, of course, Ray Fisher - have totally turned me round on Victor Stone.
I've been looking forward to seeing Zack Snyder's Justice League since it was announced, but had always considered it simply an "Elseworlds" alternate take on the characters, and a chance to see what should have been in 2017 under better circumstances.
And I'll watch any big budget superhero flick anyway, because I still can't believe we live in age where the comics I read as a child (and am still regularly reading) are being made into box office-topping blockbusters.
With its prevalence on the silver screen and small screen, the superhero genre has become as ubiquitous as westerns were in the early days of Hollywood and television, the new American (global?) mythology.
However, Zack Snyder's Justice League far exceeded my expectations and deserves all the awards that I hope are showered upon it.
It may be four hours long, but it doesn't feel it. Never does the pace drag, nor are there any corny or uncomfortable scenes, or substandard CGI creations, to take you out of the moment.
Let's put it this way: about two hours in, I was already planning on watching it again.
Without a doubt, Justice League is Zack Snyder's tour de force.
It's such a pity that Warner Bros has decreed that the earlier, inferior, cut of the film remains canon in the DC Extended Universe, when really all copies of it should be shovelled into the same landfill as the E.T. The Extra-Terrestrial video game.
Yet, while Zack Snyder's Justice League is a magnificent conclusion to the Snyderverse trilogy, it now also seems highly unlikely that we will see the continuation of this storyline and the resolution of the movie's apocalyptic cliffhanger.
The fans who campaigned for years for Warner Bros to "release the Snyder cut" have been rewarded and we have all got to share in that reward.
Thank you, fans. Thank you, Zack.
- In the UK, Zack Snyder's Justice League is currently only available through Sky Cinema.