(M) ****

Director: Kenneth Branagh.

Cast: Chris Hemsworth, Natalie Portman, Tom Hiddleston, Stellan Skarsgard, Idris Elba, Kat Dennings, Anthony Hopkins.

A SIGH of relief. That's what you'll hear from many Marvel movie fans after they see Thor.

Expectations were high, yet there was this niggling fear among some - how will the film-makers reconcile a Norse god/superhero from another planet/plane with the more realistic approach of the Iron Man movies and The Incredible Hulk?

So that sigh is because they found a way. And not just any way. Thor is exciting, entertaining and enjoyable, plus it puts the Marvel movie series back on track after the mis-step of Iron Man 2, and edges us ever closer to the Biggest Comic Book Movie Event ever, The Avengers (due next year).

For those not brushed-up on their Norse mythology or their Marvel comics, Thor (Hemsworth) is the son of Odin (Hopkins) and the brother of Loki (Hiddleston). He wields a big hammer called Mjolnir, loves smashing Frost Giants, and he can fly.

But unfortunately, he's also brash and cocky, and after re-sparking a war with the Frost Giants through his own arrogance, Thor is banished from his home in Asgard, stripped of his powers and dumped on Earth.

There he meets a team of scientists (Portman, Skarsgard and Dennings) and takes a lesson in being human as he battles a force that is trying to keep him from returning home.

Thor's secret weapon is its sense of humour, plus the surprise pick of Branagh as director. Best known for his love of Shakespeare and fopping about hilariously in one of the Harry Potter movies, Branagh proves an ideal choice to helm this. There is something definitely Bard-like in Thor's plot machinations, with its familial and regal twists and its themes of humility, jealousy, and proving one's worth.

It's not without its flaws, of course. There are probably too many characters - aside from Thor's immediate family, there's also his warrior off-siders and a gatekeeper, plus the Earth-bound trio of scientists and SHIELD's Agent Coulson (Marvel series regular Clark Gregg)- and few get developed as much as you'd like, particularly Portman's Jane, but the cast does a great job with what they've got, doing a lot with a little.

Strangely, some of the special effects are rubbish. In this day and age, with this kind of budget, that shouldn't happen. Also, Branagh goes crazy with the lens flares - an ever-increasing bad habit, seen most prominently in Michael Bay movies and the recent Star Trek. Sure, a couple are okay, but when directors go over the top with them they just become distracting.

But there is a lot to like here, especially Hemsworth. He is excellent as the hammer-wielding god of thunder, making one of Marvel's more far-fetched characters eminently believable, and is ably met by Hiddleston as his brother Loki.

And lens flares aside, you can't help but feel Branagh has done a superb job at grounding its more fantastical moments, and ensuring nothing feels too silly or over-the-top.

Fans rejoice. Not only do you get a great movie here, but there is also a neat cameo and a very revealing post-credits scene that points towards The Avengers. Bring on Captain America in July.