Spider-Man 2 (PG)

A skilfully woven web

When was the last time you saw a superhero being fired from his job as a pizza-delivery boy? That is the first of many humiliations to be endured by Peter Parker (Tobey Maguire) in Sam Raimi's Spider-Man 2, a sequel that not only outstrips its predecessor but has a perversity and quick-wittedness that hardly seem to belong in a comic-book movie. It's about a crisis of conscience: Peter is falling behind on his rent, is failing the grade at college, is feeling generally exhausted, all because his alter ego, Spider-Man, is too busy swinging through the high-rise canyons of Manhattan, fighting crime. Public duty has sabotaged personal choice.

Worst of all, his double life is losing him the love of his dream girl Mary Jane Watson - MJ (Kirsten Dunst). She's baffled by his hesitant courtship, little realising that he's afraid that her life will always be in danger from Spider-Man's enemies. When Peter doesn't show up at the theatre for MJ's starring performance in The Importance of Being Earnest - another tale of love and disguise - she takes it as evidence of his flakiness, whereas Peter has been diverted en route by yet another summons to keep New York safe from wrongdoers. Oh, what a tangled web he weaves...

Raimi and his screenwriter Alvin Sargent (with "story" input from the novelist Michael Chabon) shrewdly avoid the cheap attractions of parody and camp and instead imagine how human frailty and loneliness might affect a superhero. In this regard Maguire is a good choice for the title role, since his faraway look and sleepy voice seem rather more l'uomo vague than dynamic crimebuster: most of the time he appears to be in need of a decent night's kip. His spiritual unease becomes manifest in the malfunctioning of his Spider powers. His hands and feet are losing their prehensile strength, and he can no longer rely on the great looping skeins of webbing he used to shoot from his wrist. Peter tells a doctor that "a friend" of his has had dreams in which he is a failing Spider-Man; when the doctor kindly suggests that identity involves a choice, a light clicks on in Peter's eyes - maybe he doesn't have to be Spider-Man at all.

But renouncing his heroic self isn't as simple as it looks. He can witness a mugging in a back alley and walk away, but will he allow himself to do the same when the whole city is in peril? The menace comes in the shape of a scientist, Otto Octavius (Alfred Molina), whose backfiring experiment with fusion leaves him with four retractable metal tentacles coiling around his body like Medusa's snakes. "A guy named Octavius winds up with eight limbs - what are the odds?!" barks the truculent tabloid editor J Jonah Jameson (J K Simmons, relishing every moment of his unpleasantness). "Doc Ock", as he is known, makes for a much better supervillain than the first movie's Green Goblin; where the latter simply cackled hysterically, Molina's chunky torso floats above his limbs in sinister arachnoid fashion, and announces his approach with footsteps as thunderous as a T-rex. Hopes that you-know-who will save the day seem to have been dashed when a vagrant goes to the tabloid with the trademark red-and-blue Spidey-suit he has found discarded in a bin. Editor Jameson offers to pay him $50. "I could get more than that for it on eBay", whines the tramp.

But destiny will out, and our hero must eventually answer the rescue call. As in the first movie, there is something weightless and flimsy in the spectacle of Spider-Man swinging between the Manhattan scrapers, and the question of what he swings from remains uncertain. Tarzan had his vines, but Spider-Man seems to be slinging his jets of goo into thin air. Otherwise, Raimi and his production consultant, Neil Spisak, deserve credit for resisting the urge to create a mausoleum of design; instead they manage to finesse a crisply shot New York with a vivid comic-book overlay, and the cinematographer, Bill Pope, even finds room for the occasional grace note - a lovely Hopper-esque shot of a laundromat at night, and a nod to Warhol, too, as Peter walks distractedly past a wall covered in multiple poster images of MJ.

It's unusual and gratifying to find a multimillion dollar movie that's been put together with some thoughtfulness, that doesn't neglect subtlety in between delivering the smash-bang-wallop. Indeed, it combines them very winningly in a scene where MJ and Peter, tremulous with romantic longing, are on the verge of kissing when their tender moment is shattered by a car flung full at them through a café window: we are suddenly reminded why Spider-Man felt driven to forswear his love in order to protect her.

There are dull patches, and James Franco as Harry Osborn, scion of the Green Goblin, seems to be working himself up into a permanent state of angst, yet even he is a beneficiary of Raimi's generosity with a close-up, his eyes glistening with unshed tears. A showdown will be inevitable in the next sequel.

It's the interest in human fallibility that sets this movie apart. The superhero who bridles at his own responsibility may not sound an especially gripping prospect, but his dilemma is explored with a conviction that, within the fantasy genre, feels almost groundbreaking. "Intelligence is something to be used for the good of mankind," says Octavius before his calamitous mishap, a line that would provoke jeers in your average blockbuster. But it doesn't in this movie.