“At least we all agree, the third one is always the worst,” concludes Jean Grey (Sophie Turner), leaving the multiplex after seeing Return of the Jedi with her fellow Gifted Youngsters.

It’s a bold gag, but X-Men: Apocalypse never quite disproves her assertion. That’s not to say we’re in The Last Stand territory, as far as X-trilogy closers go, but this never quite reaches the high bar set by First Class and Days of Future Past, prequels that threw Marvel’s mutants into period settings with élan.

Directed by Bryan Singer, the franchise’s trusted leader, Apocalypse doesn’t lack ambition, pitting the superteam against their biggest opponent yet. The titular big bad is an ancient Egyptian, believed to be the very first mutant, with godlike powers and a following to match. His knack for transferring his consciousness into younger vessels as required makes him damn near immortal.

A full-pelt opening set in the Nile Valley, 3600 BCE, sees Apocalypse in the midst of taking over a younger body (Oscar Isaac, briefly glimpsed out of make-up), before rebels interrupt the ceremony, trapping him underground for millennia. He reemerges in 1983, looking to recruit ‘Four Horsemen’ to assist in his plan to cleanse the world of its weaklings before starting afresh (it’s his thing, apparently).

Meanwhile, Mystique (Jennifer Lawrence) is hiding in non-blue human form after becoming a mutant icon for saving President Nixon at the end of the last film, some 10 years ago; Charles Xavier (James McAvoy) is enrolling new recruits into his school; and Erik ‘Magneto’ Lensherr (Michael Fassbender) is living an idyllic family life in Poland, keeping a low profile with factory work. And that’s not to mention a whole other bunch of familiar faces, both new and returning… The roster is vast enough to make Civil War look like a two-hander. Apocalypse comfortably feels like the biggest X-Men movie yet, and Singer, master of the ensemble, does a decent job of keeping it all just about coherent as we globetrot from plot strand to plot strand.

The action is similarly huge, from the pyramid-razing antics of the opening sequence to a final multi-mutant smackdown on a scale that dwarfs previous entries in the franchise. When you have a villain who’s all but omnipotent, it takes a lot of heroes to go up against him. In fact, there’s so much going on that it becomes a bit exhausting at times, and anyone lacking a half-decent grasp of the mythology thus far should probably sit it out. It doesn’t exactly welcome newcomers.

With so many characters to serve, some are inevitably shortchanged. It helps that First Class was so well cast, with McAvoy, Fassbender and Lawrence slipping back into their roles with ease, bringing gravitas to go with the backstory baggage. The new class is also extremely appealing; Tye Sheridan makes for a cooler Cyclops than James Marsden, Kodi Smit-McPhee is a spot-on Nightcrawler (turns out that bamf-ing is still a hell of a lot of fun), and Game of Thrones’ Turner brings the required poise and angst to Jean Grey. Of the Horsemen, Psylocke (Olivia Munn), Storm (Alexandra Shipp) and Angel (former EastEnder Ben Hardy) certainly look the part, but there’s no time to give them anything like discernible character traits.

Apocalypse similarly fails to carve out much in the way of distinctive characteristics. Isaac has recently been proving himself one of the most versatile actors of his generation, but buried as he is under masses of make-up and impressive body armour, he’s unable to convincingly sell the baddie’s motivation or powers. Quite why he actually needs the Horsemen is never particularly clear. And when his world-ending plan starts to come into effect, there’s little in the way of perspective to put it into context, making it hard to appreciate the magnitude of the stakes in a way that never troubled the history-specific climaxes of its predecessors.

With their sprawling casts, the X-Men movies have always been at their strongest in the smaller beats between the big set-pieces. Apocalypse features some surprisingly dark violence (Angel’s ‘upgrade’ will have younger viewers squirming), balanced out by some nice one-liners. With armageddon imminent, the humour never completely disappears. Quicksilver (Evan Peters) even gets to reprise his slo-mo superspeed, even if it’s not quite as thrilling as DOFP’s standout sequence.

By the end, we’re still some way from joining up with Singer’s 2000 X-Men, so there’s plenty of scope for plugging the gap. On the evidence of this offering, it might be wise to spend a little more time focusing on the core line-up at the X-mansion before looking outwards again: going home before going bigger.