“With great power comes great responsibility” is the mantra that drives Peter Parker’s dual lives, but it also can be just as aptly asked of Sony Pictures, the movie studio that made “Spider-Man” and “Spider-Man 2” the summer movie events of 2002 and 2004.

With each progressive film in the arachnid superhero’s saga costing more and more to make, the onus is on Sony to make the third installment of Sam Raimi’s trilogy the most extravagant and exquisite hero adventure yet. And to drum up further anticipation for the massively-hyped, $258-million “Spider-Man 3,” Sony has released an extended cut of the first Spider-Man sequel on DVD, which runs eight minutes longer and is billed as “Spider-Man 2.1.”

This sequel picks up two years after the events of the first “Spider-Man” film. Peter (Tobey Maguire) has drifted away from high school pal Harry Osborn (James Franco) and love interest Mary Jane (Kirsten Dunst). He precariously juggles two part-time jobs while majoring in physics. All this takes a back seat to his pursuits as Spider-Man.

Complicating matters is Peter’s newfound friendship with Dr. Otto Octavius (Alfred Molina), a brilliant physicist who believes his fusion experiments could provide cheap, renewable energy for all of New York City. But when the experiment goes wrong and permanently bonds four artificially-intelligent metal arms to his body, Octavius goes mad and begins wrecking havoc on the city as Dr. Octopus. Peter’s now charged with stopping his one-time idol, while fighting aside lingering doubts about the costs of his double life.

Unlike many sequels, “Spider-Man 2” improves upon its predecessor with startling ease and grace. Sure, its action sequences are more thrilling, but that is an expectation of almost any second attempt. Bigger is not always better, but “Spider-Man 2” towers over many of its superhero compatriots because it has that rare mix of heart, character and humanity that makes us care for Peter Parker, the college student, as much as Spider-Man, the superhero.

By grounding the action around Peter’s hard-luck life, Raimi invests his main character with a complexity that is missing in far too many summer blockbusters. And Maguire, to his credit, matches Raimi’s directorial skill by making us ache for his perpetually arms-length love for Mary Jane, the evolving relationship that remains the heart and soul of the franchise.

True to their word, Sony Pictures’ new “Spider-Man 2.1” DVD improves upon the film’s theatrical cut. It’s amazing to see how far Raimi, who supervised many of the re-additions, manages to stretch those eight minutes. On paper, that number doesn’t sound all that impressive, especially against the formidable 50 minutes Peter Jackson added to “The Return of the King” on that film’s extended edition.

But just about every addition here is a solid one. Nearly every scene in the movie benefits from a few extra shots, and “Spider-Man 2.1” benefits from this even distribution. Mostly, this accounts for quiet character-revealing moments such as the scene where Peter sits alone in his cramped one-room apartment, listening to a police scanner while fighting thoughts of Mary Jane and a quieter life.

For bonus features, “Spider-Man 2.1” includes a new commentary track with writer Alvin Sargent and producer Laura Ziskin. While not as engaging as the track with Raimi and Maguire, it reveals more about the all-important story and character choices that made this film so special.

Among the new featurettes is “With Great Effort, Comes Great Recognition,” a compelling look at the Academy Award-winning special effects team that keeps the franchise on the cutting edge of its field and “Visual Effects Breakdown,” which reveals how the spectacular train sequence was accomplished.

“Spider-Man 2.1” is the third release for the film on DVD. This fact alone should set spider-senses everywhere tingling, particularly since movie studios swindle away a fortune on re-releases. But rest assured Spidey fans, this one may actually be worth a fair shake. It makes a great movie a little bit better, and sets the bar that much higher for the wall-crawler in “Spider-Man 3.”