Matthew Vaughn’s X-Men: First Class is a welcome return to form for the X-Men franchise after the risible X-Men: Last Stand and the sloppy Wolverine origins story. The ’60s setting allows for a lighter tone than previous instalments but Michael Fassbender’s intensity as Erik Lehnsherr takes the film to some dark places.

The subtitle of the film is a misnomer. Ostensibly a film about the origins of Charles Xavier’s “School for Gifted Youngsters”, First Class is far more about the relationship between Lehnsherr and James McAvoy’s Xavier than the formation of the X-Men, with most of the young mutants here being some of the lesser-known names from the comics — Havok, Darwin, Angel Salvadore, etc. instead of more familiar crowd-pleasers of previous films.

It’s Fassbender and McAvoy that really steal the show. Fassbender gives a typically intense performance as an embittered Nazi hunter while McAvoy’s Xavier acts as a sensitive and intellectual counterpoint. I don’t think anybody would have complained had the film been only about these two; there’s more than enough material and both actors are capable of carrying a film. Fortunately the ensemble cast doesn’t overwhelm the film and the younger cast members, for the most part, put in decent turns. Nicholas Hoult, formerly of About A Boy and Skins is excellent as nervy scientist Hank McCoy, and Caleb Jones as Sean Cassidy and Jennifer Lawrence as Raven are also noteworthy.

The cast isn’t perfect. Kevin Bacon as Sebastian Shaw seems to be the only villain of the piece having any fun at all, his wordless sidekicks limited to looking stylish in expensive suits, and, in the case of January Jones’ Emma Frost, flaunting her tits as if she’s auditioning for a role in The Benny Hill Show. Jones plays Frost entirely as she plays Betty Draper: mean-spirited, ice-cold and tedious to watch for more than a few minutes.

Rose Byrne as CIA agent Moira MacTaggert takes a central role but doesn’t have much to work with, and also suffers the indignity of having to play her introductory scenes running around in nothing but sexy underwear, a gratuitous moment but sadly typical of how the female characters here are treated; I don’t think there was a single female character that wasn’t seen barely-clothed at one point.

Finally, Lucas Till as Alex Summers maintains the franchise rule that no member of the Summers family may have any discernible personality.

The X-Men films have always leant toward the darker side of the comic spectrum — more Batman Begins than The Fantastic Four — and while First Class is no different, the ’60s setting — all polo necks and mini-skirts and Green Onions — allows for a lighter overall tone than previous films despite some gruesome moments from Lehnsherr.

The film is long but doesn’t feel like it, with enough action sprinkled between the character scenes to always feel like things are moving forward. If anything, things are a little too brisk at times. Hank McCoy’s transition into Beast is almost incidental and Raven’s character arc would have been more believable had it been extended into a second film.

In fact, despite being more reserved than previous X films, First Class can still feel as if it’s trying to squeeze in a few too many familiar comic book tropes — character names, Cerebro, spangly outfits and such — than there’s time for. That said, we’re not burgeoned by the endless roll-call of mutants that bogged down Last Stand and Wolverine. The film is packed but doesn’t suffer from it.

Sadly we do have to sit through the obligatory scene where the young mutants pointlessly come up with their ‘secret mutant code names’ — Havok, Mystique, etc. When a comic book film tries so hard for serious realism these scenes are always awkward — the first X-Men suffered from this as well — and the younger characters bestowing names on Erik and Charles is particularly heavy-handed.

Quibbles about corny character moments aside, First Class is a qualified success, and feels like a natural and worthy companion piece to Singer’s first two X films.

Best of all: there is no 3D version of the film. You can watch it in 2D and you can damn well like it.