Iron Man

There's now a very clear sliding scale on which any new superhero movies must be placed before they're pushed into production. At one end is the candy-coloured, day-glo fluff of the Fantastic Four, while at the other is the dark and brooding sincerity of Batman Begins. In other words, you're either in it for the money, or you're taking this shit seriously. Director Jon Favreau has pitched Iron Man slap-bang in the middle of the scale and has managed to have his cake and eat it: Iron Man just opened to a $200 million weekend plus critical adoration across the board. Not bad for a former swinger.

The buzz on Iron Man has been positive right from the beginning. Comic-book fans can smell a faker from a mile off, but Favreau treated Stan Lee's source material with the greatest respect, including the fans on every aspect of the movie's production via his MySpace page. Iron Man is Marvel's first self-financed movie, meaning there's no bothersome studio interference and only committed artists working towards creating a united vision. The end product is an almost perfect superhero movie, with enough cool action scenes to satisfy the average cinemagoer plus an abundance of character to keep fans of the comics onside. It's no surprise that Iron Man 2 has already been slated for a 2010 release, and it's no surprise it's already got people drooling in anticipation.

As origin stories go, Iron Man shares more than a few similarities with this summer's other superhero - for Tony Stark, think Bruce Wayne with a personality and a busted moral compass. Stark is a billionaire playboy genius who makes his money from weapons manufacture, but when he's captured during a presentation in Afghanistan by swarthy, bearded terrorists, he's forced to build them a killer missile. While in captivity, Tony has a change of heart (literally, when his shrapnel-filled chest is fitted with a powerful electro-magnet) and Stark busts loose in his Mark I metal exo-skeleton, dishing out metallic justice to any henchmen stupid enough to be standing in his way. Iron Man is born, and Stark vows to use his upgraded suit to protect the people he's put in harm's way.

Favreau's first stroke of genius was in the diversity of his casting. Robert Downey Jr. is a perfect fit for Stark, channelling his bottomless charisma into an obnoxious, womanising jerk but making him totally lovable with it. It's impossible to see anyone else playing the role - to think Tom Cruise was once attached to the project just seems perverse. Downey Jr enjoys great chemistry with Gwyneth Paltrow's personal secretary Pepper Potts, and the two flirt amiably throughout. Paltrow shows more warmth here than she has in her entire career; it helps when you're acting opposite someone as naturally charming as Robert Downey Jr.

Jeff Bridges is a revelation as villain Obadiah Stane, the business partner who is forced into retaliation when Stark's unexpected moral U-turn almost ruins his company. For the first two-thirds of the movie, Stane makes for a fine foil to Stark, a money-driven businessman in pursuit of the almighty dollar, shipping weapons overseas under the radar and generally acting in a very un-Dude-like manner. The superhero story-book dictates that every superhero needs a super villain, and the last reel sees Stane suit up himself to square off against Stark in a titanic clash of iron on iron. Bridges is somehow less commanding under a mountain of mecha-armour - perhaps it's due to his crappy name. The Iron Monger was clearly last in line when they were handing out badass villain handles. Nonetheless, Stane is one of the more three-dimensional foes in recent comic-book lore - there are no Green Goblin-esque theatrics needed here.

This is far and away the most ambitious film Jon Favreau has attempted (his last two movies were Zathura and Elf) but he proves himself to be more than capable in handling a $180m budget. The later fight scenes rival Transformers in the 'fighting robots' geek-boner department, while the opening Afghan assault is frantic and disorientating, Stark spilling out of his Humvee and getting a glimpse of a bomb with his own logo on it seconds before it explodes. It's typical of a movie with a thick streak of humour running through it - Stark enjoys an amusingly strained relationship with his house's robots and his test-flights contains plenty of physical comedy gut-laughs. Favs gets the balance spot-on - Iron Man is funny without being silly, yet can kick ass to the moon and back when the chips are down. Top marks for the metal/rock soundtrack, too.

Iron Man is a film full of beginnings. It could be the start of a great summer of blockbusters, although the jury's still out on Hulk. It also looks like being the making of Robert Downey Jr, Movie Star - a well-deserved career boost indeed. More importantly, however, it signals the beginning of a killer era for Marvel, who can now start thinking about franchises and potential crossovers. Fans of the comics will spaz at the last reel mention of the SHIELD agency, and those wise enough to wait until after the credits will get a truly tantalising glimpse of where Marvel could be headed (two words: Avenger Initiative). We can but dream until 2010, but in the meantime... well, it's your move, Dark Knight. Ali