“The Amazing Spider-Man” was one of those movies that is better than it had any right to be.

It only existed because Sony needed to produce a film with the character in order to keep the film rights, but it was stylish, fun and well cast.

Its sequel, “The Amazing Spider-Man 2,” can largely be described in the same ways, but it’s simply packed so tightly with subplots and characters that it overstays its welcome by a fair margin and ends up being a disappointment.

To summarize the plot in an efficient manner might be difficult, but it’s worth a try. Peter Parker and his on-and-off girlfriend Gwen Stacy (Andrew Garfield and Emma Stone, respectively) have just graduated high school, and a scholarship offer in England for Gwen leaves the couple’s future uncertain.

Meanwhile, Peter’s old friend Harry Osborne (Dane DeHaan) returns from abroad to see his dying father off before assuming control of their megacorporation Oscorp Industries. Harry finds out he has the same terminal illness his father had and decides he needs Spider-Man’s blood to inherit the hero’s fast-healing abilities.

While all of this is going on, the film shoehorns in another villain, a lonely, Spider-Man-obsessed Oscorp engineer (Jamie Foxx) who understandably becomes super angry when he’s accidentally given electrical superpowers in a way that makes about as much sense as being bitten by a radioactive spider. He promptly starts calling himself Electro and wreaking havoc on New York City, as comic book super villains tend to do.

“The Amazing Spider-Man 2” basically suffers from the same problem as the reviled “Spider-Man 3,” despite being made by entirely different people. Both films simply have too much going on. Osborne and Electro are both fairly decent villains on their own, but their stories don’t get enough development because the film is constantly trying to juggle three or four different subplots at a time.

Those subplots are fine on their own. The problem is the story is structured and paced so poorly there are long stretches of time where it’s difficult to care about anything that’s going on.

The beginning and end of the film are action-packed, but the middle agonizingly drags on and gets bogged down in exposition that simply isn’t good enough to carry a movie without being broken up by action. It also doesn’t help that the story basically ends, goes on for another 25 minutes, and then ends again.

When “The Amazing Spider-Man 2” actually becomes a Spider-Man movie, it’s a decent popcorn action movie. There are a few neat sequences where slow-motion is used as a visual representation of the web-slinger’s spidey-sense, and Electro’s ability to manipulate power grids is represented by some solid special effects. The sound design is nice as well, as every Electro power blast makes a loud dubstep-esque tone.

Like in the first film, the performances stand out and help a little to hide the bad parts. Garfield’s wisecracking Spider-Man is infinitely preferable to Tobey Maguire’s brooding emo-kid depiction of the character. Stone is as good as usual, and DeHaan’s slimy version of Harry Osborne is overdone in an entertaining way. It’s fun to see Foxx play a soft-spoken nerd at the beginning, but that version of the character unfortunately goes away far too early in the story.

Sadly, those positive elements don’t do enough to lift “The Amazing Spider-Man 2” out of the realm of mediocrity. The story actually goes in some intriguing directions, but it’s so clumsy in its approach that it’s difficult to recommend to anyone but the most ardent Spider-Man fans.

Here’s to hoping the inevitable third film sticks to just one villain.