The Dark Knight Rises (15)

Bane's game: Tom Hardy stars as the film's villain, leading a criminal gang (Ron Phillips/2012 Warner Bros)

This concluding part of Christopher Nolan's Dark Knight trilogy goes out with a bang – a big one – though the ringing in your ears as you leave the cinema may have less to do with exhilaration than puzzlement. For while one accepts the mayhem of explosions and mechanised roars as an inevitable adjunct of the modern blockbuster, it is long swathes of the dialogue that have scrambled the brains and bamboozled the reason. This isn't merely a problem with the story's villain, who talks through a mask that covers 80 per cent of his face; even characters with fully operational mouths and noses deliver lines that become, in the film's murky sound mix, indecipherable.

Intensity, rather than clarity, is this franchise's strong suit. For those who prefer their superheroes flawed and difficult, Bruce Wayne has certainly provided a Dark Knight of the soul. Eight years since his last public appearance, he now hobbles around his huge mansion on a stick, less the playboy billionaire than a frail recluse. He can't even be bothered to put up a fight when his late mother's pearls are stolen from under his nose by a comely burglar, Selina Kyle, aka Catwoman (Anne Hathaway). It seems the authorities regard Wayne's elusive alter ego Batman as "a thug in a cape", blaming him for the death of Harvey Dent, the crusading District Attorney who supposedly made Gotham City safe from crime. Only world-weary police Commissioner Gordon (Gary Oldman) knows the truth – that it was Batman who saved the day back then, not the two-faced Dent.

But the sleep of reason and the retirement of superheroes beget monsters. Down in the sewers of Gotham a crack army of terrorists has been preparing a coup on the city's rich elite and it arrives in the form of a brutal assault on the stock exchange. Their leader is a rippling hunk of muscle named Bane, whose face is shrouded by what looks like a gasmask made from the shell of a carbonised crab. He's played by Tom Hardy, foghorning his lines in an ac-tor-ly, sonorous boom, and woe betide anyone who dares reply: "Pardon me?"

He likes to strike a pose, this Bane, hands high on his lapels like some old-school northern industrialist who calls money "brass". Hardy is among several actors that Nolan has rehired from his previous outing, the conceptual thriller Inception (2010). Marion Cotillard plays wealthy philanthropist Miranda Tate, who wants to enlist Wayne on her green-energy project; Joseph Gordon-Levitt plays a beat cop who's twigged to Wayne's secret double-life; and Cillian Murphy, who was Scarecrow in the first of the trilogy, Batman Begins, is glimpsed late on as the judge of a mob-ruled court.

Bane and his crew are making their escape from the stock exchange when a certain caped crusader appears on the scene to give chase. You can't keep a good (Bat)man down, it seems, even when Gotham has been so ungrateful for his previous rescue missions. The plot, adopting an apocalyptic tone, sets up an almighty ding-dong between Bane, who presents himself as the city's liberator, and Batman, who we know is the city's protector. Bane's ragtag army of looters are soon running amok, while Batman's allies are either in hospital (Oldman), in hiding (Oldman's deputy, played by Matthew Modine), or in a huff (Michael Caine's paternalistic major-domo Alfred). There's no telling whose side Hathaway's Catwoman is on, creeping along the edges of the film, though she is key in fomenting the big smackdown between Bane and Batman. When these two put up their fists, the punches they land are like the noise a fridge would make if you pushed it off a high building. It is hardly more realistic than those cartoon graphics (POW! ZAP! KER-BOOM!) of the Batman show on 1960s' telly.

Those TV shows look homely next to the bombast of the present franchise. Along with the muddied sound of The Dark Knight Rises, the cumulative effect of the screenplay is portentous and deadening. It compounds the impression of a filmmaker who has sacrificed his quicksilver wit and invention for grandiosity – and length. Nolan hit the ground running with his debut Following (a lean 69mins) and then his masterpiece Memento (113mins). Since then the running time has steadily bloated, with Batman Begins at 140mins and The Prestige at 130mins. The Dark Knight leapt to 152mins, Inception almost equalled it (148mins), and now The Dark Knight Rises clocks in at an astonishing 164mins. This would be permissible if the film had other astonishments to match, but, aside from a late switcheroo of one character's loyalties, the movement of the film is all grind and no glide. That includes a bizarre cameo by Tom Conti, performing surgery on our hero's back as crude as the foreign accent he's faking.

The never-ending parade of comic superheroes transplanted to the screen has thrown up some unexpected stars. Who would have thought Robert Downey Jnr could polish up the role of Iron Man to such a pleasing gleam? Andrew Garfield has also surprised as the new Spider-Man. Bale is capable of great things (The Machinist, The Fighter) but he's a sullen, awkward presence as Batman, and short of humour. That lugubrious character leaches into the film. Of course we know that Wayne is a man haunted by the murder of his parents and possibly demented by his sense of duty. But he also gets to kick ass, use some cool gadgets and shine his Bat-signal over the city. Surely some of it must have been fun?