In Avengers: Age of Ultron, a movie that cost more than the GDP of Palau, the most impressive effect is James Spader’s voice. As the eponymous supervillain, Spader is heard rumbling from the digital matrix like Tom Waits before his morning coffee. It’s not the a voice that’s particularly suited to an artificial intelligence hellbent on world domination, but it lends a welcome dose of humanity to a bad guy who’s otherwise generic in a movie full of brand names.

Spader sounds tired, and it’s hard to blame him in this disappointing sequel. Every blockbuster series is prone to bombast fatigue, and the Avengers franchise was particularly vulnerable. With a growing corps of heroes up to and including a Norse god, it’s hard to keep raising the stakes. In the crew’s first film together under writer/director Joss Whedon, who returns here, it took another legendary immortal as well as a wormhole full of Alien knockoffs just to slow this posse down. How can you top that?

With a villain as big as the Internet, it turns out—though Ultron, as cinematic artificial intelligences are wont to do, slides into a suitably impressive robot body so that his foes will have something tangible to molest.  First, though, this motley wolf pack have to dispatch a more mundane army marshaled by a mad scientist who operates out of a quickly-impregnated impregnable fortress in the fictional Eastern European country of Sokovia. (The current IRL geopolitical situation, scary as it is, has been a boon to fantasy filmmakers who have been visibly relieved to go back to having good old-fashioned forces of evil from the vicinity of the Iron Curtain, as opposed to the Middle Eastern fundamentalists filmmakers felt compelled to summon for the first decade of the century.)

There, the Avengers meet a couple of new weirdos who are initially hostile—but who we know from the posters will ultimately end up flying through the air in the same direction as the true blue comrades who sprung them from their citadel. One of the most disappointing surprises of Avengers: Age of Ultron is how miscast and underused Elizabeth Olsen is. Here’s an actress who could breathe life into the most sterile of actionscapes, but instead she plays a sulky empath with an ill-fitting accent and a perpetual pout that puts the film’s 3D technology to the test. Her brother (Aaron Taylor-Johnson) is a lighting-speed runner with a bleached-blond mop of hair and a quasi-futuristic track suit; he looks like a reject from the Sokovia Olympic team circa 1996, suggesting that at least the film’s costume design team had a sense of humor—a quality that largely eludes Whedon this time around.

Age of Ultron is not without its chuckles, but it’s a dyspeptic slog compared to its predecessor, which had a lot of fun with the friction among its wacky cast of characters. Here, the characters’ signature traits—Captain America’s mid-century moral code, Iron Man’s hubris, Thor’s highflown diction—are reduced to stale punchlines, and not very many of them at that. When Captain America chides his colleagues for profanity in the first scene, it’s a cute moment…but then it comes up again and again and again, and you start to realize that Whedon’s imagination won’t be at its most fertile.

The script is peppered with cheap no-homo jokes, which are doubly offensive given that the major movie studios still apparently feel that America’s not yet ready for an openly gay superhero—just beefy bros who are more paranoid about any whiff of homoeroticism than they are about existential threats to life as we know it. As if concerned that he still wasn’t being heteronormative enough, Whedon gives us a scene in which two of the heroes bemoan how “monstrous” it is that, for reasons related to their origin stories, they’re unable to conceive children. Set in the playroom of Hawkeye’s kids, the scene underlines the film’s insistence that a real hero should be able to—and want to—settle down in a mountain cabin with an attractive member of the opposite sex and start pumping out babies. I miss the days when Captain America’s Eisenhower-era sensibility was a joke instead of an assumption for the Avengers.

The film finally starts to loosen up around the time that the Avengers are taking an extended escape from their domestic arrangements to enjoy some street fighting in a flying city. At long last the gags start to land along with the punches, and composers Brian Tyler and Danny Elfman tag-team to bombard us into submission with soaring music as the enhanced Avengers team up against the infinite hordes of robots that Ultron considerately sends at them in continuous waves, like flocks of ducks flying over a blind. Finally matters are resolved for the moment, even as we’re assured that the Avengers will return to battle a much more absurd enemy. That guy’s cameo during the closing credits is a welcome omen: after this tedious tussle, it’s time for the Avengers to make like Weird Al and dare to be stupid.

– Jay Gabler