Forget the weather changing. Forget the preponderance of beachwear in the supermarkets. Forget the Radio Times doubling in size under the weight of extra advertising. Once the blockbusters start invading the multiplexes, you just know it's summer time and there are few event movies that do not conform to the five commandments of the Blockbuster Bible: 1. Thou shalt think up five big action sequences and only then worry about the screenplay as an afterthought. 2. Thou shalt create a villain seemingly twice as powerful and smart as the hero. 3. Thou shalt make sure that a small thing telegraphed in the middle of the plot becomes significant at the climax (thou knowest the drill, the oxygen tanks in Jaws, the Body Suit Loader in Aliens, the glasses of water in Signs). 4. Thou shalt build in a scene that can be effortlessly integrated into a computer game or some such profitable outlet. 5. Thou shalt not be too smart and thereby dissuade the masses to attend. And yet... Iron Man contradicts a few of these rules but still manages to look and sound like a blockbuster. But it has one thing most blockbusters do not have and we'll come to that in a moment.

Yes, the CG effects are terrific (metal, as well as insect carapaces, are not as difficult as animals to be made to look photorealistic via CGI). The music is heavy metal, driving and weighty but alas no discernable theme unless we count the "duh duh, duh-duh-duh-duh"). Jon Favreau's direction is light and unshowy and he coaxes out a naturalness from all in his cast with apparent ease. The design of weapons manufacturing billionaire Tony Stark's world is eye catching and his own personal system software is a dream. It's nice to imagine that some day, we may integrate so effortlessly with software/hardware combinations. The supporting cast is rock solid with a nod to Terrence Howard as Stark's long suffering best friend and a shaven headed Jeff Bridges managing to erase all memories of 'the Dude abiding' from The Big Lebowski in his role as the deranged company man. But there's a special nod to an actress who's been off our screens for too long. Living in the Celebiverse as we do, it's easy to lose track of someone's gift amidst the plethora of paparazzi pix. The only place Gwyneth Paltrow has been is splashed all over the front pages for simply being pregnant. Her return in Iron Man as Pepper Potts is welcome in that she is much more than a high heeled power secretary. She manages to be in control, vulnerable, in self denial and engorged with passion all in the same moment. She is the perfect foil to Tony Stark and it's an on-off, will they-won't they relationship which I look forward to watching develop in the sequels. And that decision's a shoe-in surely with the movie capping $100 million over its first weekend.

If there are down sides, it's seeing two robots, essentially, slugging it out after last Summer's Transformers had made me robot-averse. But that's the spectacle that blockbusters are bound to deliver. The major downside is an offshoot of something I've whinged about in these pages many times before; the creeping invulnerability of the human action star. And don't start telling me it's all fantasy so it doesn't matter. Of course it matters. If you want me to care something has to be at stake like the hero's life at the very least. Can I repeat a physical law here, one that would have taken the talented writers of Iron Man (Fergus and Otsby) just moments to address? If a human being – in an incredibly futuristic metal suit that can fly and do the most amazing things, granted – drops from the sky and lands on the ground, the only bits of Tony Stark left based on that impact would be his teeth fillings. The rest of him would be soup. It is not the contact with the ground that needs to be survived but the sudden stop. Maybe the suit could have had an emergency anti-gravity device that would bring the suit (both low tech and high tech ones) down like a plane, horizontally. In the movie, Stark hits the ground at the appropriately named 'terminal velocity' three times which would have killed him in the most final way possible. Suit or no suit, you drop from a height and unless you slow down before you stop, you're paté, OK?

In the second of Stephen Fry's seemingly extemporaneous 'podgrammes' ("Bored of the Dance"), Fry attempts to eviscerate, dismember and bury the oft-repeated idea that Americans do not do irony. This is as dismissive a stereotype as – oh, so many to choose from. How about the one that presupposes I can sing and commune with sheep because of where I was born. It's tempting to use stereotypes in humour and when desperate to criticise but the simple fact is that despite our genetic similarities, we're all unique sums of our experiences, intellect, rationality and fear. So whereas Mariam may get and appreciate irony and Juanita doesn't, it matters not one whit that one is Afghani and the other Portuguese. We have relationships with human beings not national clichés. This brings me on to a man who embodies almost all the clichés of stardom and yet, through a sandstorm of negative publicity, drug busts, small arms offences and a serious talent under the weight of self destruction, ladies and gentlemen, I give you Robert Downey Jnr.

A lot of press has been devoted to the rather clichéd redemption story. "Isn't it great that a talented actor beset with personal demons a-plenty has been given a second chance?" Yes, I suppose it is but if you're casting a 135 million dollar movie (and it's Marvel's first completely home financed picture) your leading man has to be (a) attractive to women, (b) attractive to men, (c) able to pull of a good haymaking punch and (d) – optional – have a wit about him that enables his character to rise up above blockbustorial confines. Yes, someone with a past of unreliability and self-destructive tendencies is not the safest bet but Favreau knew in his gut it was the right call and go against those instincts at your peril. Think about the character of Tony Stark, a man who has to run the gamut of performance from arrogant drunken womaniser to scared shitless, genius mechanic, mourning a friend, having an epiphany for peace, near wooing his personal assistant and finally becoming the titular character, wise cracks and all. Downey Jnr. not only makes us like the bastard but respect him too. His charm and lightness of touch makes the metal man movie soar. His dialogue (whether rigorously scripted or Downeyised) never, ever feels like he's even rehearsed it in terms of its naturalness. It just comes out and only on a second viewing can you catch up with some gems. Let's be honest. Iron Man is a 21st Century Knight in armour who saves damsels and daddies in distress. But it's Downey Jnr.'s show and everyone knows it.