Call him a square, or maybe a guy who has run out of new tricks, but no one could rightly label the hero of Spider-Man 3 a slacker. For 2 hours and 19 minutes, Peter Parker (Tobey Maguire), in the guise of his web-spurting alter ego, does fierce battle with a dissolving molecular-mutant shape-shifter called Sandman, who might have risen from the digital desert of a Mummy sequel. He also confronts Venom, a reptile-headed prancer of an alien, as well as Harry Osborn (James Franco), his old comrade/nemesis, who's all too eager to retrofit the Green Goblin mask and flying skateboard of his late father. On the home front, Peter must deal with a girlfriend, the lovely Mary Jane Watson (Kirsten Dunst), who feels frozen out by him, not to mention the biggest baddie of all: the hidden demon that lurks inside. All in all, that's a heavy burden to pile on Tobey Maguire's star-child gawk and perpetually curled baby lips. It's also a lot to ask of moviegoers, who in this jumbly, sometimes fun, sometimes dispirited sprawl of a sequel end up getting more bang for their buck...and also less.
Spider-Man 3 has terrific moments, but after the danger and majesty and romantic brio of Spider-Man 2, those adrenalized rooftop ballets feel, more than ever, like sequences: hermetic action miracles cooked up in the effects lab, with a story patched around them. Sam Raimi, directing his third Spidey adventure (the script is by Raimi, his brother Ivan, and Alvin Sargent), tosses together the rivalries, criminals, and amorous mishaps like salad, and he contrives a way to make Spider-Man into a figure of ''alienated'' vengeance without ever risking the tiniest sliver of audience market share.
In Spider-Man 3, an asteroid crashes, just as in the old '50s sci-fi movies, and out of the fiery rock emerges a sticky, shiny black tangle beware! It's the crawling audiotape! that, for no discernible reason, heads straight for Peter, infesting his cruddy apartment like fleas waiting for a dog. The alien stickum is searching for a host, and when it finds one, it brings out the host's latent dark side.
His suit now black as a tire, Spidey, possessed, leaps over rooftops, pursuing a foe to what looks like a grisly demise. This time, he has a private stake in the square-off: Sandman, before emerging, Hulk-like, from a grand atomic snafu, was a desperate criminal named Flint Marko (Thomas Haden Church), who may have been responsible for the murder of Peter's uncle. The movie tells us, after the fact, that Spidey was doing his best to kill Sandman, yet the vengeful act in question looks closer to an accident, so the distinction between the ''good'' and ''bad'' Spider-Man is never more than cosmetic. It boils down to how abstractly demonic he looks in that shineless black suit.
Peter, by contrast, wears the dark side on his sleeve, if not his designer lapels. He's exorcising a more profound demon: the curse of nerdishness, which makes Maguire play every scene with the same dorky strangled whine and am I just nice or trying to get you to join a cult? good-guy stare. There's got to be an escape from that Tobey daze, and as the crawling audiotape from space takes over, Peter lets loose, and Maguire lets his hair down or, at least, lets a shock of it fall onto his forehead. It does him good. As he saunters down the sidewalk in a black suit, doing snappy Rat Pack things with his fingers, Maguire seems to be enjoying himself, even if it isn't clear whether the girls are giggling at him because Peter is suddenly sexy or because he seems to have lost his mind. When he wanders into a jazz bar, where M.J., now estranged from him, is singing a set, he looks tough, talks tough, and finally takes over the floor of the club. At last, we see the secret that lies in Spider-Man's heart: It's Peter Parker's desire to dance as if he were in a revival of Cabaret.
Okay, I kid, but it's only because Raimi sets up the whole dark-side-of-a-hero business and then treats it like a Jim Carrey joke. Meanwhile, the movie lurches along on quasi-contrivances. You never see why M.J., after being fired from her play, neglects to tell Peter, or why, on a day honoring Spider-Man, he's willing to jab at her jealousy by restaging their famous upside-down kiss with the blond tart Gwen Stacy (Bryce Dallas Howard). Topher Grace, as Peter's rival photographer, a smarm in frosted Brad Pitt hair, brings the movie a welcome dose of seething energy. And let's not take the effects scenes for granted. A few of them are indelible, like a vertiginous sky-high office disaster that evokes 9/11, or Sandman's tornado-to-giant-fist morphings, or the climax, with its scary plunging taxicabs. Spider-Man 3 is product, but it's a machine that tickles your eyes.