What's eating Peter Parker? Lots. Torn between duty and his love for Mary Jane, Spider-Man's alter ego suffers a debilitating identity crisis in this emotional sequel to 2002's blockbuster.

An introspective superhero is nothing new, but turning Spider-Man into a lovesick puppy is risky. Moviegoers might complain too much time is spent on feeling and not enough on action, particularly in the movie's brooding middle section. Yet while the relationship arc takes precedence -- encounters with the villain, while top notch, seem like afterthoughts -- the combination love story and effects-laden spectacle is remarkably entertaining, ensuring the franchise will go down as among the best comic book adaptations ever. The sophomore slump does not apply.

The glue that holds Spider-Man 2 together is humor. Jolts of character-grounded levity bridge the mushy moments and Spidey's acrobatic crime stopping. Apparently the best remedies for low self-esteem are a good joke and, when the opportunity presents itself, i.e., you pass a burning building, the daring rescue of a child. An inspirational speech by Aunt May (Rosemary Harris) and the potentially catastrophic experiments of a new villain dubbed "Doc Ock" also help snap Peter out of his self-doubting funk.

At the outset, our harried friend is juggling school and work, worrying about his Auntie, and struggling to pay the rent on his dingy apartment. Best friend Harry (James Franco) resents Peter's shielding of Spider-Man, whom he blames for his father’s death; and actress-model M.J. (Kirsten Dunst) is frustrated by his unwillingness to move their friendship to the next level. She's dating an astronaut, who happens to be the son of his obnoxious editor (J.K. Simmons). Adding insult to injury, Peter's fired from his pizza delivery job.

The deeper source of his depression is gradually made clear. He feels bound to protect M.J. from the dangers of being a superhero's lady and yet can't stop thinking about her. Consequently his powers start to fail him. He has to wear glasses and starts firing blanks -- no web spinning for this angst-ridden arachnid. Resolving to hang up the spider thing altogether, Peter reverts back to the pre-Spidey nerd. In illustrating the change, director Raimi offers a hilarious sequence accompanied by Burt Bachrach's "Raindrops Keep Falling on My Head."

The threat posed by Dr. Otto Octavius (Alfred Molina), whose revolutionary work on fusion is being financed by Harry's company, seems less lethal than Peter's internal struggle. Octavius is a sympathetic figure with noble motives prior to the accident that turns him into a tentacled villain. His flaw is scientific hubris, not the megalomania implied in his boast, "The power of the sun in the palm of my hand!" Clunky Doc Ock is controlled by four mechanical arms and, unlike Spider-Man, isn't an elegant creature. He lacks his adversary's physical grace, so well accentuated here and in the first movie. But Spider-Man can't shirk his duty after Doc Ock nearly kills Aunt May and then kidnaps M. J.

The transitions between Peter's personal crisis and his several battles with Ock are facilitated by small jokes such as the colors from Spidey's suit running in the wash, or a busker singing versions of the Spider-Man ditty. First-rate editing and Danny Elfman's music also help Raimi move effortlessly between the quotidian and the nearly apocalyptic and so strike a balance between personal drama and action spectacle.

While visually beautiful, Spider-Man 2 is so successful because it is deftly structured as drama. Peter's personal maturation and the exploits of a larger-than-life hero, capable of rescuing a packed subway train, are both memorable. But the last shot of the movie -- M.J. gazing at her sensitive man as he swings off into the sunset -- puts an exclamation point on the human-interest angle. 

(Released by Columbia Pictures and rated "PG-13" for stylized action violence.)