Eleven movies into Marvel's sprawling cinematic universe, we expect certain things from the studio's biannual superhero extravaganzas: loads of action, a few Easter eggs hinting at the direction of the coming installments, and plenty of Joss Whedon-y quips and snarky banter in between all of the explosions.
The first "Avengers" movie was an impressive juggling act. Whedon (notable as the only Marvel director to receive sole writing credit on his films) was able to weave together the threads of the preceding installments and deliver a satisfying action movie with heart. But now with "Avengers: Age of Ultron," it seems there's just too much to balance. The film not only has to catch us up on our established heroes -- Iron Man/Tony Stark (Robert Downey Jr.), Captain America (Chris Evans), Thor (Chris Hemsworth), the Hulk/Bruce Banner (Mark Ruffalo), Black Widow/Natasha Romanoff (Scarlett Johansson), and Hawkeye (Jeremy Renner) -- but also introduce several new characters while laying the groundwork for the next phase of movies. The result is messy and overstuffed, and that messiness translates to a feeling of unevenness. For everything that works, just as many elements fall flat.
"Age of Ultron" also doesn't get to benefit from the innate excitement that came from seeing these characters coalesce as a team for the first time. As this film opens, we see how they've settled into their roles, working together to take down a Hydra base. It's during this battle that we're introduced to super-powered twins Wanda and Pietro ("Godzilla" co-stars Elizabeth Olsen and Aaron Taylor-Johnson), known to comic fans as Quicksilver and Scarlet Witch. Olsen makes the most of her role, though Quicksilver fails to make much of an impression; Bryan Singer put the character to much better use in last year's "X-Men: Days of Future Past."
In their role as protectors of Earth, the Avengers can only do so much, and Tony Stark becomes convinced that a better long-term plan is needed, ultimately deciding that the best course of action is to build an armor shield around the earth. He and Bruce Banner set about creating an artificial intelligence (which seems to be the theme of the year so far, with "Chappie" and "Ex Machina" recently offering their own takes on the subject), dubbed Ultron. Unfortunately, Ultron quickly gains sentience (and a voice provided by James Spader) and reaches the conclusion that the true threat to the world is the human race.
Marvel still has a problem coming up with compelling villains to match its heroes, and Ultron does nothing to alter the pattern. He makes a great, intimidating first appearance, but as he upgrades himself over the course of the film, he evolves into a slick CGI creation with a penchant for sarcasm, and the character's menace deflates bit by bit.
Besides the action, what audiences have really responded to in Marvel's films are the characters. The talented cast is able to bring life and distinct personalities to these heroes, and "Age of Ultron" excels in its development of Black Widow and Hawkeye -- the human Avengers who've gotten short shrift in Marvel's overall film universe. When you're on a team with a super soldier, a god, a tech-genius billionaire, and a scientist rage monster, it can be difficult to pin down what an ordinary human might bring to the table. Whedon's script argues that it's their humanity that actually holds the team together. I can't hate a movie that allows such a large role for my favorite Avenger: We get to see a bit of Hawkeye's home life, and in one of the best moments of the film, he gets to give a crucial pep talk. Natasha's sweet, flirty romance with Bruce Banner is handled well, even if that relationship seems to have developed out of nowhere. A vision sequence offers a tantalizing glimpse of Natasha's backstory, but also functions as a depressing reminder that there are still no official plans for a standalone Black Widow film.
"Ultron" comes together during its action-packed climax; Whedon knows how to juggle large scale action divided between a huge cast of characters and it's undeniably thrilling to see the entire Avengers team band together to stop the robot menace. Still, with the lineup of Marvel movies scheduled out through 2019, the release of each new installment has started to feel obligatory, and the continued announcements only serve to diminish the stakes in each film. It's difficult to worry too much about whether our heroes will triumph when we know they're due to appear in a sequel next year. It says a lot that when the now traditional "The Avengers will return" title card came up following the end credits, I heard a voice from the front of the theater mutter an unimpressed "well, yeah."