Avengers Assemble always had potential to be both the best and worst of the Marvel universe silver-screen adaptations; a hulking ‘best of’ with an all-star cast or a lumbering, mechanical bore laden down with shoe-horned fan-service. With Joss Whedon at the helm, fans (of his own creations and of the properties now in his hands) were always going to be optimistic, but such matches made in heaven haven’t always avoided development or box-office hell.

Director Nick Fury (L. Jackson) begins the film in no mean fix. His coruscant, cubed MacGuffin has gone awol in the hands of the Asgardian Loki, as have top agent Hawkeye (Jeremy Renner) and genius prof Erik Selvig (the wonderfully eccentric-looking Sellan Skarsgård) thanks to a little mind-control. What follows is a classic example of team-building in both senses, with all the attendant sly motivational tricks, followed by your usual cataclysmic showdown. Thankfully, each of the film’s component parts stands up to closer scrutiny (well, mostly) to reveal an early contender for best goofy blockbuster of the year.

Much of the film’s class stems from the delicate pacing, in terms of plot points and introducing the key players. Even the obligatory rock-’em sock-’em set-up that gives Samuel L. a superabundance of brusquely pragmatic quips doesn’t outstay its welcome, introducing Loki’s alien puppet-masters with a disorienting air of real menace before letting him crack on with obliterating a S.H.I.E.L.D research base, taking in a car chase and helicopter crash in the meantime. It’s not exactly break-neck, but it does set the tone, and Whedon throughout has a canny knack of mixing character building, action and exposition into a seamless three act structure.

The Buffy/Firefly maestro isn’t always given the best tools to work with however, but by and large the cast hold it together. As to be expected, Downey Jr’s Tony Stark gets all the best lines; some genuinely thought provoking character observations and others more typically flippant and comic. Mark Ruffalo’s Bruce Banner manages his reluctant helper/raging live wire act solidly enough to make you forget about Edward Norton (for now) but it’s home-grown Tom Hiddlestone as the manipulative, power-mad Loki who far out-shines his fellow cast. Balancing on a knife-edge between petulant younger brother, (to grizzled Hemsworth’s Thor) and self-righteous conqueror, between silver-tongued operator and droll sadist, his versatile delivery alone compensates for the wooden rigidity of Chris Evans (Cap Am) and Scarlett Johansson (Black Widow).

Still, the action is visceral, the cinematography surprisingly deft in places, and the long-awaited concurrence of Marvel superheroes done perfect justice by a frequently engaging and occasionally hilarious script more than makes up for the odd dud note. There are some sly meditations on the usual moral dilemma of whether S.H.I.E.L.D is being totally honest with its new agents, some interesting nods to the checkered pasts of the so-called good-guys, and some pleasingly grey areas surrounding Fury’s motives and the inter-rivalries of Cap Am vs. Iron Man, Thor vs. Iron Man, and... Stark really does have all the best lines

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All told, Avengers Assemble doesn’t and never wanted to do anything new or overly through provoking. The film’s brief was always going to be difficult enough, and with more 'serious' comic-based blockbuster The Dark Knight Rises looming on the horizon it was always going to have to tow a different tack. Surprisingly hilarious in parts, appropriately self-referential, and possessed of plenty of muscle-bound gusto, Whedon has succeeded over and against the odds to hold up a mirror to the rag-tag team of mutants and geniuses and produce a film much more effective than the sum of its parts.