Grade: C

Sam Raimi made Spider-Man swing in the first two installments of this mega-series—the 2002 original was excellent, and the 2004 sequel even better, one of the best super-hero movies ever made. But in the comics the Web-Slinger has occasionally lost his grip and come crashing to earth, and that’s what happens here, too. As if to prove the old adage that bigger isn’t necessarily better, “Spider-Man 3” is both overstuffed and undernourished, with a plethora of villains and too many extraneous sequences (some of them positively embarrassing). Even most of the necessary scenes go on too long, and many of the action set-pieces (most notably the elaborate finale) are overly reminiscent of those from the earlier pictures. The best one can say of it is that it works hard to tie up all the loose ends from the initial two films, but unhappily it does so without a similar sense of enjoyment and simple flair. By comparison to “Spider-Man” and especially “Spider-Man 2,” this is a major disappointment.

Plot-wise the new picture continues to adhere to the pattern established in the “Superman” movies: the first episode was the origins story, and the second the one in which the hero hangs up his tights but then puts them on again when danger demands it. Now the third “Spidey” has the hero, like the Man of Steel in “Superman 3,” forced to face his own evil side. The means of bringing this about is to lift the Venom scenario from the comics, with Spider-Man (Tobey Maguire) first affected by the aggression-inducing “symbiote” from space that turns his costume black and his personality nasty, and then—after he manages to divest himself of the parasite—the oily goo attaching itself instead to disgraced photojournalist Eddie Brock (Topher Grace) who, blaming Spidey’s civilian self Peter Parker for his humiliation, aims to destroy him.

This was actually a good choice of plot for the third picture, and it provides a few fine moments, most notably the church tower sequence in which Parker rips the symbiote from his body—an agonizing process—and it takes over Brock instead. Had the story been treated throughout with equal depth, it could have achieved real mythic power. But instead the script by Raimi and his brother Ivan dilutes it, shortchanging Grace, who’s not terribly well cast in the part but might have invested Brock/Venom with more personality if given the opportunity, and portraying the alien’s effect on Parker in ways that don’t work at all. The shots of “bad-boy” Peter strutting down the street, ogling every passing girl and showing off his stuff, may have had their intended comic effect if they’d lasted thirty seconds or so, but Raimi returns to them so often that they become tiresomely unfunny. (It’s almost as though they were padding in a picture that, at 140 minutes, doesn’t need any.) But even worse is the elaborate sequence in which Parker, to demean his girlfriend Mary Jane (Kirsten Dunst), from whom he’s temporarily estranged, brings another girl, Gwen Stacy (a bland Bruce Dallas Howard), to the bar where MJ’s working, and then indulges is an absurdly athletic (and nearly endless) dance. Maybe it was intended to give Maguire a chance to show off, but it just stops the movie dead in its tracks and may well leave you slack-jawed.

And that’s not the only example of misguided musical decisions in “Spider-Man 3.” A good deal of the romantic plot thread with MJ is devoted to her disappointing singing career, which not only gives Dunst the opportunity to sing two numbers (poorly) but turns her character into a whiny, self-pitying drag one for much of the running-time—a part Dunst, quite peevish and shrill here, fills all too convincingly. And as if that weren’t enough, at one point MJ, feeling abandoned by Peter, visits Harry Osborn (blankly grinning James Franco)—another holdover from the previous installments—with whom Parker must eventually come to terms over Osborn’s desire to take vengeance against Spider-Man for killing his father in the first film. (To do so, Harry takes on the identity of the Green Goblin, his dad’s old villainous alter-ego.) And in a sequence that plays like an out-take, Mary Jane and Harry indulge in dancing the twist while preparing breakfast—a routine that, like Maguire’s in the bar, goes on interminably.

The basic Venom plot is further undercut by a decision to add yet a third villain to the mix (a misjudgment comparable to the one that doomed the various sequels in the initial “Batman” series). This one is Sandman, the alter-ego of escaped con Flint Marko (Thomas Haden Church, curiously anonymous), who turns out to be the actual killer of Parker’s Uncle Ben. The whole plot thread involving him is not only anemic, despite some pretty good effects for the character, but too weepy, involving as it does Peter’s ultimate coming to terms with his surrogate father’s death and replacing his desire for revenge with forgiveness. If handled sensitively, this aspect of the story could have had some real dramatic resonance. As it is, though, it’s played mawkishly, with too many scenes of characters tearing up at the drop of a hat. One of the strengths of the earlier pictures in the series was that they had heart as well as humor and action. But here while the ingredients may be the same, this time they’re miscalculated and badly mixed: too often the heart becomes bathos, the humor strained farce, and the action mere bombast.

Of course, there are still sequences that are rousing, if overlong. An initial battle with Osborn opens the picture with a roller-coaster-like ride, a sequence involving a runaway crane is impressive if somewhat plastic, and a couple of confrontations with Sandman show some imagination. But what’s intended as the piece de resistance—a big battle in the final reel, with Harry, Sandman and Venom all involved with Spidey as a captive Mary Jane dangles in a car high above the city streets—will be awfully familiar to anyone who knows the original “Spider-Man.” And it seems endless.

Throughout, it must be said, Maguire still shows himself an actor of considerable charm, even when forced to do those smug saunters down the streets or that misconceived dance bit. To be sure, he sometimes overplays the boyish naivete, and one wishes the script hadn’t demanded him to indulge in quite so many tear-jerking moments. But overall he keeps Peter a likable fellow in his natural state, and seems to be having more fun playing the young man’s dark side than we have watching him do so.

But he doesn’t get much support from Dunst, Franco, Church, Grace or Howard, and those further down the cast listing don’t fare all that well, either. Rosemary Harris, as Aunt May, and J.K. Simmons, as Jonah Jameson, merely repeat their bits from previous installments, with diminishing returns; the later in particular is stuck with farcical material that’s definitely second-rate. And joke bits from Raimi confederates don’t carry the punch that was clearly intended. The inevitable Bruce Campbell shows up for a comic cameo as a maitre d’ in a French restaurant, which comes off nicely at first but, as usual, is overextended. But the performance of the cadaverous John Paxton (Bill’s father), as Harry’s butler Houseman is disastrous, several steps below amateur level. His presence is all the more painful in that James Cromwell, who could have brought some real panache to the role (as he did to Prince Philip in “The Queen”), is instead wasted in a nothing part as Gwen’s policeman father. And the seemingly obligatory cameo by Stan Lee is even more tiresome usual; only the most devoted fanboy will react positively to yet another appearance by the old ham.

Technically, of course, “Spider-Man 3” is accomplished; any movie whose budget exceeds a quarter billion dollars should be. But even in this respect it’s somewhat of a disappointment after the second installment. In Part Deux, as in the first picture, there was a certain degree of restraint in the effects sequences, and they were handled very smoothly, even if they could never be termed realistic. Here one gets the sense that the makers are trying to overwhelm viewers with their CGI magic, perhaps to distract from the movie’s more fundamental weaknesses. Unfortunately, the emphasis on them merely accentuates their flaws. In this, as in so much else in the picture, a more sparing approach would have been the wiser course. And a final weakness may be noted. The first two “Spider-Man” movies were marked by excellent scores by Danny Elfman. But here Elfman’s been replaced by Christopher Young, whose contribution is far less engaging and effective, workmanlike rather than inspired. That’s somehow characteristic of the overall decline this film represents.

Of course, “Spider-Man 3” will be a smash hit, and will rake in big bucks. But in terms of quality the trajectory of the series proves to be like that of the original “Superman” movies, or even the first “Star Wars” trilogy, in which the initial installment was good, the second even finer, and the third a distinct letdown. Let’s just hope that if the franchise continues, it won’t fall to the level of “Superman 4” or “The Phantom Menace.”