Another summer season, another superhero spectacular — these are the days (and nights) of our moviegoing lives. The one under review today, Marvel’s “Avengers: Age of Ultron,” isn’t half-bad, largely because of its director, Joss Whedon. Here’s a guess: Some viewers will love it, others will hate it, and still others will yawn at its very existence. None of this matters because the most relevant thing about a movie like this is that its quality is almost entirely irrelevant. It was created to crush the box office, entertainment media and audience resistance, and mission, you know, already accomplished. In an age of lock-step entertainment, pushback isn’t just immaterial; it is also suspect.  This is a familiar lament, especially from those of us who didn’t grow up worshiping at the altar of Stan Lee et al. or don’t watch movies based on brand affiliation. (Guilty!) It’s a good question whether the big studios’ dependence on comic books is hurting American mainstream cinema and whether they can figure out how to survive without suckling at Marvel’s great multiplatform teat. For a Marvel agnostic like me, the single most interesting thing about “Age of Ultron” is that you can sense that Mr. Whedon, having helped build a universal earnings machine with the first “Avengers,” has now struggled mightily, touchingly, to invest this behemoth with some life.  The Times critic Manohla Dargis reviews “Avengers: Age of Ultron.”  He has and he hasn’t — in a movie that is by turns a diverting and dreary blur of babbling and fighting that translates into faces in close-ups or bodies in longer shots. The gang’s all here, of course, including the billionaire egoist Iron Man (Robert Downey Jr.); the straightedge hero, Captain America (Chris Evans); the E.T. Viking with the hammer and hair, Thor (Chris Hemsworth); the token chick, Black Widow (Scarlett Johansson); some dude with arrows, Hawkeye (Jeremy Renner); and that computer-assisted leviathan, the Hulk (Mark Ruffalo). Rounding out the A-listers is Samuel L. Jackson, who as Nick Fury brings a beautiful bald skull along with an Old Testament vibe and a black leather coat straight out of Shaft’s closet. Mr. Jackson has a nine-movie deal with Marvel; he has two more to go.  If you’re not acquainted with the intricacies of the Marvel universe, it can be hard to keep track of who’s doing what to whom and especially why. In story terms, the movie — Mr. Whedon wrote “Age of Ultron” as well as directed — is outlandishly overpacked, taking place on multiple fronts against various foes both terrestrial and galactic. Mr. Whedon opens with one of those Bond-style blowouts that’s so old-fashioned it even includes a Nazi-type villain, Strucker, whom the German actor Thomas Kretschmann plays all too briefly with a sneer and a monocle. Strucker evokes the continental cads à la Erich von Stroheim and is meant to be a Mengele type whose work has produced a special set of twins: the Scarlet Witch (Elizabeth Olsen) and Quicksilver (Aaron Taylor-Johnson).  The most powerful superheroes in the world, Iron Man, Captain America, Thor, Hulk, Black Widow and Hawkeye try to stop the villainous Ultron from enacting his terrible plans.  Like much of the rest of the main cast, Ms. Olsen and Mr. Taylor-Johnson are appealing, attractive performers who usually show up in independent productions that probably cost less to make than this one’s craft-services bill. Their newness to this world distinguishes them when the screen becomes too crowded; so do the intensity of their contrapuntal performances and the pathos of their characters’ back story as refugees turned lab rats. Mr. Whedon is a sensitive director of actors, as he showed for years while shepherding “Buffy the Vampire Slayer.” His characters banter and quip like screwball loons while parading their cultural literacy (here, someone name-drops Eugene O’Neill), but these are linguistic fig leaves for men and women who feel and hurt deeply.  The upshot here is a movie that lumbers along like a front-line tank, hauling the enormous weight of the entire Marvel enterprise along with it, only to routinely work itself into a frenzy of action and then (shades of the Buffyverse) chill out with scenes of relaxed camaraderie, challenging romance and domestic intimacy. A lot of effort has been expended so that the Hulk can make like a big baby with tantrum issues, tossing cars and whatnot around like toys, including in a disastrously protracted street brawl that stops the movie dead. Once the character reverts to ordinary form as Bruce Banner, though, Mr. Ruffalo lifts his every scene, as does Ms. Johansson, even if she doesn’t have much to do but strut in her form-fitting costume and exchange meaningful looks with a romantic foil.  A preview of the film.  These too-short interludes of the Black Widow grappling with a difficult love interest modestly humanize the movie, which helps a bit with both its rhythm and scale, making it less of a monotonous special-effects blowout. Repeatedly, Mr. Whedon injects something alive into the mix, be it a woman’s fingers tenderly caressing a computer-generated wrist or children leaping into a father’s embrace. This assertion of flesh-and-blood vulnerability extends to several narrative points, including a nod at the military industrial complex that is almost touchingly pointless given how much of this movie has been dedicated to ensuring obliterating violence looks cool. Even the villainous alien, Ultron, playfully voiced with mellifluous menace by James Spader, philosophically chews the cud about humankind.  Mr. Whedon chews over the same in “Age of Ultron” (war and people, what are they good for?) in his efforts to personalize the material while dutifully hitting all the genre notes. This “Avengers” doesn’t always pop the way that the first one sometimes did, partly because its villain isn’t as memorable, despite Mr. Spader’s silky threat. And, as is often the case in these comic-book movies, most of the fights are interminable and fatiguing, though Mr. Whedon does fold in moments of beauty, including when the image slows down with each Avenger centered in the frame both together and individually. This centering crystallizes the dynamic that is paramount to the Avengers story and also suggests the behind-the-scenes push-and-pull battle that Mr. Whedon has waged over two movies.  “Avengers: Age of Ultron” is rated PG-13 (Parents strongly cautioned). The usual bloodless mayhem and massacre.  Written and directed by Joss Whedon, based on the Marvel comic book series; director of photography, Ben Davis; edited by Jeffrey Ford and Lisa Lassek; music by Brian Tyler and Danny Elfman; production design by Charles Wood; costumes by Alexandra Byrne; produced by Kevin Feige; released by Marvel Studios. Running time: 2 hours 21 minutes.  WITH: Robert Downey Jr. (Tony Stark/Iron Man), Chris Hemsworth (Thor), Mark Ruffalo (Bruce Banner/Hulk), Chris Evans (Steve Rogers/Captain America), Scarlett Johansson (Natasha Romanoff/Black Widow), Jeremy Renner (Hawkeye), Don Cheadle (Col. James Rhodes), Thomas Kretschmann (Strucker), Aaron Taylor-Johnson (Quicksilver), Elizabeth Olsen (Scarlet Witch), Paul Bettany (Vision), Cobie Smulders (Maria Hill), Stellan Skarsgard (Erik Selvig), James Spader (Ultron) and Samuel L. Jackson (Nick Fury).  A version of this review appears in print on May 1, 2015, on page C1 of the New York edition with the headline: Getting the Superband Back Together. Order Reprints| Today's Paper|Subscribe
The new installment in the “Avengers” franchise adds characters, including the Scarlet Witch and Quicksilver, even as its familiar heroes fight battles terrestrial and galactic.