When it comes to superhero movies, the third time is never the charm.

From “Superman III” to “X-Men: The Last Stand,” they hit a creative pothole after the second installment. If anyone could change that, it would be Christopher Nolan, whose Batman adaptations have ranked among the best genre films of all time.

But while “The Dark Knight Rises” is much better than most third entries, it’s still flabby and convoluted.

It has been eight years since the events of “The Dark Knight,” and Bruce Wayne (Christian Bale) has gone into seclusion, allowing the late D.A. Harvey Dent’s supposed heroism to inspire a successful crackdown on Gotham City’s organized crime. Commissioner Gordon (Gary Oldman) is still keeping the truth to himself, and the Batman has become a half-remembered villain among the populace.

The calm is shattered by the arrival of Bane (Tom Hardy), a hulking madman with an army of devoted followers and a shadowy connection to Bruce’s old mentor-turned-nemesis, Ra’s Al Ghul. Bane presents himself as a revolutionary who wants to take back the city for “the people,” a Robespierre-like figure turning genuine grievances into a reign of terror. His real goal is indiscriminate destruction, and his motivations get murkier — and sillier — as the movie progresses.

Nolan (scripting with his brother, Jonathan) spends a good hour on exposition, putting all the pieces carefully into place before allowing any forward movement. He introduces not only Bane, but Selina Kyle/Catwoman (Anne Hathaway), rookie cop John Blake (Joseph Gordon-Levitt) and pretty socialite Miranda Tate (Marion Cotillard), who play important roles alongside the many new and returning characters.

Some of them are interesting, but they aren’t developed fully. Selina is a slick, fearless con artist, and Hathaway almost reaches the Catwoman standard set by Michelle Pfeiffer in “Batman Returns.” John has a haggard nobility that Gordon-Levitt seems to absorb from Oldman in their scenes together. Even Miranda gets a backstory beyond “generic love interest.”

Bruce/Batman isn’t completely bereft of development — his decision to bring his alter ego out of mothballs leads to a rift with Alfred the butler (Michael Caine) that gives the actors a couple of emotionally affecting scenes. Their debates about sacrifice and responsibility rehash material from the previous films, but they at least provide some thematic focus.

Once the action finally gets going, it obliterates everything in its path, including boredom and narrative cohesion. Nolan can stage an epic blow-out like nobody’s business, especially in IMAX. He gives the audience a taste of what’s to come in the opening stunt that introduces Bane, and the rest of it is worth the wait. Nolan loves his crazy gadgets almost as much as Bruce and tech genius Lucius Fox (Morgan Freeman) do, so there’s no shortage of excitement when he pops open the toy box.

It’s overwhelming, though, and that need to make everything as huge as possible is at the root of the film’s problems. This might be the last one in the series (Nolan has indicated as much), so the impulse is to include every idea that didn’t make it into the first two.

That invariably leads to far too many digressions involving far too many characters. We don’t need to see Bruce looking over X-rays with his doctor. We need to see how he pulls off a pivotal escape that otherwise seems to bend the rules of space and time.

“The Dark Knight Rises” is equal parts overstuffed and underdeveloped, with moments of brilliance that survive the mayhem, because Nolan is simply too talented to screw this up completely. But if even he can’t break the third-movie curse, there’s little hope for other franchises.

“Iron Man,” you have been warned.

WHAT OTHERS SAY

• Ty Burr, Boston Globe: “In case you’d forgotten — and the summer of 2012 has given us much to forget — this is what a superhero movie is supposed to look like.”

• Michael Phillips, Chicago Tribune: “Nolan’s notion of amping up the evildoing in ‘The Dark Knight Rises’ is to simply layer the slaughter in higher and higher piles, though with a refreshing lack of computer-generated imagery. … What worked beautifully in ‘The Dark Knight’ seems overworked and almost ridiculously grim.”

• Roger Ebert, Chicago Sun-Times: “Begins slowly with a murky plot and too many new characters, but builds to a sensational climax. … It lacks the near-perfection of ‘The Dark Knight,’ it needs more clarity and a better villain, but it’s an honorable finale.”