The latest Avengers blockbuster is getting almost as many raves as it has superheroes, with one critic calling it "a supremely entertaining showdown".
Avengers: Infinity War, writes The Guardian's reviewer, is an "utterly confident comic-book movie mash-up."
Featuring most of the characters from the MCU (Marvel Cinematic Universe), it shows Iron Man, Black Panther et al unite against an apocalyptic threat.
Variety says the result - out in the UK on Thursday - is "bedazzling fun".
Yet its critic does suggest that having so many superheroes populate the same film "means they're all less special".
Doctor Strange (Benedict Cumberbatch), the Incredible Hulk (Mark Ruffalo) and the stars of Guardians of the Galaxy also feature in the two-and-a-half hour film.
Their adversary is Thanos, a computer-generated villain who seeks to collect six "infinity stones" that give their owner power over reality, time and space.
Attendees at screenings held in central London on Wednesday were exhorted not to reveal details of the film's plot that are not already in the public domain.
"Don't spoil it for others, the same way you wouldn't want it spoiled for you," read a message written by the film's sibling directors, Anthony and Joe Russo.
Critics are largely adhering to this request, though the Daily Mirror's Chris Hunneysett gives away a few key details we won't share here.
"Fans will be dumbfounded by the direction the movie takes the Marvel Cinematic Universe," he writes in his five-star review.
According to Screen Daily, the film "boasts plenty of comic-book action while also making room for a darker tone and emotional resonance".
Total Film concurs, describing it as "an onslaught of action, thrills, gags and gasps" in its own five-star review.
Yet Digital Spy expresses reservations in its three-star write-up, saying "it all feels a bit rushed" and is "ultimately rather depressing".
The Telegraph's Tim Robey, meanwhile, finds fault with Josh Brolin's Thanos, suggesting he resembles an "outsize ogre-thug beamed in from World of Warcraft".
Avengers: Infinity War will be followed next April by another Avengers instalment that has yet to have an official title.
But fans will not have to wait that long for more MCU fantasy, with a second Ant-Man film due out in August and a debut outing for Captain Marvel scheduled for March.
Our verdict, by entertainment reporter Neil Smith
"Thanos demands your silence," critics were told at the packed screenings that took place on Wednesday night in London's Leicester Square.
And there will be many film lovers who will be avoiding the internet today, in case their own viewing experience is spoiled by people in the know revealing too much.
So what can we write about Avengers: Infinity War? Well, it won't ruin anything to say it's an efficient, engrossing and entertaining spectacle with some craftily sprung surprises.
Its vast ensemble cast features most (if not all) of the characters we've been introduced to over the last 10 years, many of them assembled in rewarding new configurations.
Keeping so many balls in the air has ramifications for the plot, which is spread over a number of locales and is sometimes confusing.
As they did in the two Captain America films they co-directed, though, the Russo Brothers make some bold choices fans won't stay silent about for long.