An amusement suffering by comparison with its predecessor.
Like a middle-aged man on a mission, Spider-Man 3 sags in the middle, takes a while to get somewhere, but still likes the girls, swells a progress or two, and shows some of the old idealism that fights with maturity's pragmatism. Most disappointing of all is this pre-mid-life hero, Peter Parker, aka Spider-Man (Tobey Maguire), obsessed with his love, Mary Jane (Kirsten Dunst), and his desire to marry her.
Enough already. He needs to save New York from the Sandman (resurrected villain played by a fine actor, Thomas Haden Church) and Venom (Topher Grace). Director Sam Raimi, who knows a thing or two about split-personality Spider-Men and the evil forces overcoming good men with his Simple Plan, indulges his melodramatic longings through most of the film's mid section with the endless exchanges between Peter and MJ.
Raimi does do well with the dueling good and evil theme, starting with Peter's sudden change brought on by black globs from another world. When he supposedly eliminates the Sandman for murdering his uncle, Peter is confounded by his will to do it and his moral compass, which keeps getting into his conscience. Even the Sandman struggles between his devotion to his little girl and acting like King Kong to scare the bejesus out of Manhattanites. Raimi does a service to the youngsters of the audience by stressing the importance of choices, a kind of comic-book existentialism.
But marvel Comics and Stan Lee live on. Yet, at 139 minutes (12 more minutes than SM2), SM3 is 39 minutes too long, notwithstanding the outstanding FX. SM 2 was much better, not just because Pulitzer-winner Michael Chabon was one of the writers, but because it took Doc Ock (Alfred Molina) so seriously he seemed to have more lines than Dunst, who here is petulant and self-centered enough to lose my interest. As I wrote in 2004, "[Spider-Man 2] is a movie to draw you firmly and forever into its warm web, even more than the original did."
SM3 is an add on, an amusement suffering by comparison with its predecessor.