Thor

One of Marvel's most mental mythologies gets a grand cinematic going-over by unlikely director Kenneth Branagh. It's an amiable mash-up of familiar Nordic legend and barmy cosmic nonsense, bolstered by a cast of reliable character actors and bright young things. While Branagh doesn't quite manage to harness Sam Raimi's manic energy or Bryan Singer's earnest gravitas, he does make a better fist of his proudly pulpy source material than most directors of recent Stan Lee adaptations.

The Norse gods are imaginatively cast as an alien race presiding over the forces of fire and thunder, embroiled in an ancient rivalry with a neighbouring race of demonic frost giants. Their realms are linked to ours via a cosmic tree of life, but the gateway between them has been infiltrated, leading to renewed tensions for our hero Thor, as heir to Odin's throne. When his brazen warmongering sees his father strip him of his power and cast him down to Earth's purgatorial plane, Thor must adapt to a hostile environment in order to find a way home. However, his duplicitous brother Loki has designs on his seat of power, and will stop at nothing to make his exile permanent. Only a trio of scientists working on Einstein's wormhole theories stand to help him avoid the destruction of his home as well as their own.

The film starts with extended action sequences straddling the deities' world of Asgard and the icy darkness of their enemies' domain of Jotenheim. The group of young gods includes familiar faces Tadanobu Asano from Ichi The Killer and a scene-stealing Ray Stevenson in Brian Blessed mode, while Antony Hopkins works his reliable brand of commanding camp and Colm Feore brings a noble menace to his devilish villain.

The 3D is predictably underwhelming, but the direction is thrillingly visceral, Branagh's camera whizzing about like a pinball smashing up a china shop. Elsewhere, his idea of comic book style is sometimes too reliant on canted camera angles - even dialogue scenes in nondescript locations get tilted - but for the most part he shows a definite flair for maximizing spectacle while embracing the absurd.

Branagh is especially impressive in effortlessly establishing some refreshingly fleshed out characters. The conflicted loyalties between the lords of Asgard make the scenes there fraught with intrigue, while the Earth-bound scenes manage to be charming thanks to the appealing presences of Stellan Skarsgård's sceptic and Kat Dennings' ditzy assistant. Natalie Portman is also surprisingly engaging as the star-gazing prodigy who finds her belief in the fantastic tested by Thor's arrival.

Front and centre, his character's arrogant blustering makes him hard to warm to during early scenes, but once he lands on our planet Chris Hemsworth proves a hugely likable lead, equally comfortable with fish-out-of-water comedy and macho posturing. While his Chippendale physique marks him out as a credible action hero, it's his self-deprecating manner that really makes the film enjoyable.

As with many comic-to-film franchises, the burden of setting up the characters' world(s) leads to both a momentum-sapping mid-section and a feeling of unfinished business come the credits. This might not necessarily be a bad thing in the long term; Hemsworth and Portman enjoy a nicely-played romance that sets things up for a potential love triangle between Earth and Asgard, while Loki has proven such an ambiguous, slippery character that it would be a shame for him not to return, hopefully with the truly fearsome Jotenheim villains in tow.

In his obvious effort to appease fanboys and offer bang-for-the-buck, Branagh does sometimes run the risk of throwing too much into the mix, some story elements seeming a little unbalanced in places, but his commitment to the material is always evident.

During the more fantastic scenes, the costumes and visual design are something of a mixed bag - everything is just a little too bright and shiny, whether it's the plastic garb or the glistening CGI. But the ideas are so shamelessly out-there and imaginatively employed that it's hard not to get caught up in it all; from Thor's boomerang-like mallet to the Bifröst rainbow road, Branagh revels in the intricate details of Lee's extended Viking legends. The plot hinges on iconic moments from several other stories, such as Excalibur's sword in the stone and The Day The Earth Stood Still's unstoppable golem, but Thor has enough character of his own to stand as a welcome addition to the superhero stable. It will be a great shame if he gets lost in the crowd of other, better known characters in next year's Avengers film; for now his debut adventure makes for a worthy kick-off to blockbuster season.