'Avengers: Age of Ultron' review: Slam, bam and the same ending, man

Giving the people what they want is the top priority of "Avengers: Age of Ultron," a superhero free-for-all that contains almost nothing but ka-pows, blammos and cheeky one-liners. The story, in which our heroes square off against Ultron, an artificial intelligence determined to destroy his creators, is thinner than the gutter between two comic panels, which is surely by design. It's another big-budget treat for fans who still haven't tired of seeing major cities destroyed by caped demigods.

The first "Avengers," from 2012, was an impressive juggling act by writer-director Joss Whedon, who kept his eye on four very different franchise heroes. Robert Downey Jr.'s snarky Iron Man clashed with Chris Evans' sincere Captain America; Chris Hemsworth's Thor provided deadpan comic relief; and everyone trod lightly around Mark Ruffalo's Bruce Banner, lest he explode into The Hulk.

There's more of that enjoyable interaction here, but Whedon's hands are too full. Between the countless action sequences, he must introduce a poignant backstory for Hawkeye (Jeremy Renner, still the series' lowest-wattage presence), a budding attraction between Banner and Natasha Romanoff (Scarlett Johansson) and two mutant newcomers (Aaron Taylor-Johnson as the fleet-footed Quicksilver and Elizabeth Olsen as the mind-bending Scarlet Witch). Whedon doesn't drop any of these balls; he just spins them into a blur.

If anyone stands out, it's James Spader as Ultron, a sleek robot who can quote both Nietzsche and the Bible. Though Ultron's motion-capture visage robs us of seeing Spader's trademark smirk, it's audible in his voice, honed during years of playing deliciously toxic characters such as those from 1981's "Endless Love" to NBC's "The Blacklist." He's well-matched, too, by Paul Bettany, the longtime voice of the computer Jarvis, who becomes a benevolent consciousness called Vision and finally gets a body of his own.

"The Avengers: Age of Ultron" has the same finale as the first movie. In fact, it's the same finale from many a Marvel movie: The heroes battle a horde of faceless bad guys while a doomsday device ticks away somewhere, preferably up on a high point like a skyscraper or, in this case, a giant chunk of Eastern Europe that has been sent rising into the clouds. Maybe this general scenario defines the superhero genre just as the showdown defines the Western, but it's getting highly repetitive.

The film ends with a sentence that, given Marvel's mapped-out release schedule for the next several years, would seem to go without saying: "The Avengers Will Return."