DOWNEY JR steels, sorry, steals the show in this latest cinematic plundering of the Marvel comics universe. He serves up swagger and swank and arch one-liners in place of the earnestness of Spider-Man, or DC's dour Batman. His charismatic performance holds Jon Favreau's film together when it threatens to lose its way between the crash-bang set pieces. Initially, Downey Jr is Tony Stark, a Scotch-swigging, philandering, billionaire arms manufacturer. Wounded by his own ordnance and captured in what is clearly Afghanistan - though Favreau keeps the politics deliberately vague - Stark escapes by building a suit of robotic armour around a generator implanted in his chest to keep his injured heart going. Back home he starts to question his trade, and builds a new suit with which to destroy his mis-sold armaments. He's hard on the outside, soft inside, and we know his heart's in the right place because we can see it glowing, like ET's, see? Fortunately, Downey Jr's Stark doesn't stop being flippant or flash. There are delightfully witty scenes of him trying out his armour like a new sports car, observed only by two dumb robots and a sarcastic electronic butler. Thank goodness for a hero whose flaws are arrogance and cockiness, because elsewhere, the human element is lacking. When Gwyneth Paltrow and Jeff Bridges appear as Stark's assistant-cum-love interest and his mentor-cum-nemesis, the film slows noticeably. While Bridges just happily chews cigars and the scenery, the growing intimacy between Stark and Paltrow's fetishistically-attired but prim "Pepper" Potts feels agonisingly forced. Perhaps Favreau, who wrote Swingers and directed Elf, is happier with jokes and the ironic observation of boys and their toys. Sure enough, we're soon back to Stark's Iron Man, taking a mobile phone call in his helmet while playing aerial tag with a pair of F11 fighter planes. There's a satisfyingly climactic CGI battle, but Downey Jr tops it in the witty denouement with pure acting skill. Favreau's film inevitably recalls other superhero movies because all their storylines follow a broadly similar arc. A more telling problem is that it seems to treat itself as the first instalment in an aticipated franchise. Stark's struggles here are basically internal: only at the very end does he contemplate what it means to be Iron Man. Other characters are sketched in and cued up for future glory. "Next time, baby," says Stark's bland chum Jim (Terrence Howard) as he eyes a spare metal suit. I hope there is a sequel, though. Despite its flaws, the film delivers splendidly tense action sequences, a magnetic performance from Downey Jr, and Paltrow in tight dresses and high heels. Which, for superhero fans, is a near-perfect hat-trick. And now, forgive me if I mourn the success of Martin McDonagh's first feature film, In Bruges. For one thing, I know him very slightly, and whenever a (younger) acquaintance does well, a part of me dies. But mostly, it's because I fear the theatre has lost one of its most bracing, caustic and blackly comic talents to a world where he may feel more at home but shine less brightly. It is an oft-repeated truth that McDonagh barely went to the theatre when he began writing plays in the 1990s. All his references and inspiration came from film. But his first staged script, The Beauty Queen of Leenane, detonated like a bomb when the Royal Court put it on in 1996. It was funny, cruel, merciless in its guying of the peat-bog fictions of JM Synge and John B Keane, and beautifully written. As more funny, violent, sweary plays poured out, some lazily praised or dismissed him as theatre's Tarantino — a label he shrugged off with the politically bold, paramilitary-baiting Lieutenant of Inishmore and the extraordinary dark fantasy about creativity, cruelty and family, The Pillowman. Even those upset by his work admitted he invigorated theatre. He also became one of the few people to make serious money from it. When Six Shooter, a brutally funny short film about dying which he wrote and directed, won an Oscar in 2006, though, I knew the writing was on the wall. And with In Bruges, McDonagh has proved himself a masterly film director This tale of two trapped hitmen — close in tone, ironically, to Harold Pinter's play The Dumb Waiter — shows a deft understanding of pace and pathos as well as mordant wit. McDonagh draws career-best performances from both Colin Farrell and Ralph Fiennes, as well as prodding at taboos by including a racist, ketamine-addicted dwarf who gets his head blown off But hitmen and drugs and arterial spray are more common in the movies than in the theatre. What might seem radical on stage looks like a genre piece on film. Although McDonagh looks set for a brilliant cinematic career, I don't know whether he'll produce anything with the impact of Beauty Queen or the dazzling texture of Pillowman. Since the rewards, the audiences and the potential for creative control are greater in film, I suspect he may not come back. But for his and theatregoers' sake, I hope he does.

As I write this, I've got three small holes in my right shoulder and two in my left - the result of keyhole operations to remove calcium deposits from my arm sockets. As my wife takes great and repeated delight in pointing out, I had, until recently, chips on both my shoulders. They're a bit sore now, thanks for asking, and I offer this information now only as a partial excuse for not posting for ooooh yonks.

Anyway, here's my review from the premiere of Shine a Light, Martin Scorsese's film of The Rolling Stones in Concert:

IT WAS the world's biggest film premiere. Martin Scorsese's study of the Rolling Stones in concert opened at the Odeon Leicester Square with all four of the band in attendance, and was beamed simultaneously to 100 cinemas nationwide last night.

Shot over two nights of the Bigger Bang tour at New York's genteel Beacon Theatre in 2006 - one of them a show in aid of Bill Clinton's charity foundation - this is not the most raucous of concert movies. Rather, it's a chamber piece that shows how the Stones work on stage like a piece of well-oiled antique machinery. This is due, in

Shine a Light revels in close-ups of Mick Jagger's magnetic athleticism and Keith Richards's almost narcotic relationship with his guitar.

And it spies on the quietly dynamic playing of Wood and Watts, the band's engine room.

The songs, from the opening Jumpin' Jack Flash to encore Brown Sugar, sound great. The sound engineer deserves an award: I heard lyrics I'd never understood before, and each instrumental solo stands out.

There are self-congratulatory guest appearances from Christina Aguilera and Jack White of The White Stripes, but the one who really sets the band alight is blues legend Buddy Guy. He duets exuberantly with Jagger and Richards on Muddy Waters' Champagne and Reefer, a subversive choice given we've just seen the Stones glad-hand the non-inhaling Bill Clinton.

That's about as naughty as it gets. Snippets of interviews from the Stones' 40-year career are spliced between songs, partly for comic effect, but mostly to show how long they've lasted and how extensively their lives have been documented. The backstage footage is limited to some early, hilarious shots of Scorsese sweating with exasperation as Jagger exercises control over everything from the playlist to the camera angles to the lighting design ("we can't burn Mick Jagger!" squawks Marty on hearing that prolonged exposure to one light might make old rubberlips combust).

There have been harderhitting, more controversial, films about the Stones. But none, perhaps, has captured so well the ease, and occasional frustration, of four guys who have spent more time together than most married couples. My one real complaint is that a lot of the time the shots are from low-down - there are a lot of gizzards and wattles on show. Maybe you shouldn't have been so prescriptive about camera access, eh Mick? Scorcese's imprecation to his cameraman at the very end - "up! Up!! - at which the lens spirals into the sky, sounds like him finally freeing himself from the tyranny of low-level shooting.

What else? Mike Leigh's Happy-Go-Lucky, released next week, is a real charmer, and despite Leigh's protestations to the contrary, his most cheerful and life-affirming film to date. Before I met Leigh, I happened to bump into a bunch of actors, none of whom had worked with him, who cast doubts on the validity of his famously protracted, improvisatory working methods. It struck me that having dealt for 40 years with such (ill-informed) complaints, plus the routine allegation (passionately refuted) that he sneers at his characters, it's no wonder Leigh has a reputation for grumpiness. Rather, I think he's just a bit weary of being endlessly asked to discuss matters or snipes that he considers irrelevant. I found him charming - even though I was late, thanks to the Sarkozys stuffing up central London. He was also tactfully silent when I asked him about Woody Allen's latest film, Cassandra's Dream, which features the star of Happy-Go-Lucky, Sally Hawkins, in a minor role. Good for Leigh, as Hawkins is the best thing about Cassandra's Dream, which looks as if it was written and shot in a week, with no retakes - you can actually see the great Tom Wilkinson fumbling for his lines on screen. It's a waste of a fine cast - Ewan McGregor, Colin Farrell, Phil Daniels, the indecently beautiful Hayley Atwell, and my friend John Benfield. Marc Norman, screenwriter and author of a book about the travails of screenwriting, surely got it right when he coined the term "auteuroholic" for a director who feels compelled to crank out a picture every year, regardless of quality.

Now - Persepolis. What were the French thinking when they chose this as their nominee for Best Film in Foreign Language at the Oscars, rather than the (Francophone but American-baccked and directed) Diving Bell and the Butterfly? Marjane Satrapi's graphic novel about growing up in Iran and coming to terms with her cultural heritage as an expat was justly lauded, but the simplicity of both the monchrome illustrations and the narrative that made it so successful as a book makes it seem clumsy on screen. Still, nice to hear Iggy Pop as Marjane's politically-active uncle - one of the more delightfully weird bits of voice casting I've ever encountered.

Finally - caught up with Disney's Enchanted on DVD last night, and while the brilliant conceit of animated fairytale characters plunged into the real world isn't followed through with quite the degree of remorseless logic necessary to satisfy childish minds, I do think that Amy Adams deserves some sort of recognition for her wide-eyed, devastatingly charming incarnation of princess-to-be Gisele. Perhaps she could go head-to-head with Sally Hawkins for a new award - most life-affirming performance?