In Neill Blomkamp’s follow-up to “District 9,” the South African director again uses science-fiction to comment on his own country’s apartheid past and class exploitation more generally, though this time on a wider canvas. “Elysium” proves, however, that greater expansiveness doesn’t insure greater power. Coming in the wake of “Oblivion” and “After Earth,” which also offered post-apocalyptic scenarios focused on a planet in peril, it comes across as expertly made but intellectually shallow, especially when it devolves into standard-issue he-man heroics in the last act.

The earthbound portion of Blomkamp’s script is set in a dystopian Los Angeles of 2154. The city is a gigantic ruin, with a population dressed in rags, trying to eke out an existence in a world of overpopulation and underemployment. Among those just scraping by is Max (Matt Damon), a good-natured ex-con who—as we see in flashbacks—grew up as an orphan and is now employed as a grunt worker in a factory owned by emotionless techno-wizard John Carlyle (William Fichtner). Carlyle’s company is the linchpin of the other half of human society—the space station Elysium, where an elite segment of humankind lives in pampered privilege, complete with medical marvels to cure their ills and defended against intrusion by the downtrodden masses on the planet by Carlyle’s defensive apparatus, presided over by steely, soulless homeland security chief Delacourt (Jodie Foster), who uses missiles to shoot down refugee ships daring to fly into Elysian airspace and vicious earth-based agent Kruger (Sharlto Copley) to handle problems on the surface. Delacourt is also plotting a coup on Elysium, a plan that involves her confederate Carlyle’s downloading a bunch of important data into his brain. (The reason for this is never made entirely clear, but that embedded material—which controls the operations of the status quo—is the MacGuffin of the story, the all-important element of the plot that’s at the same time tedious and impenetrable.)

Unfortunately for Max, he has a bad day when he’s first brutally accosted by the android police and then fatally irradiated in an industrial accident at work. With only five days to live, he makes a deal with his erstwhile partner in crime Spider (Wagner Moura). Spider will arrange his transport to Elysium, where he can be cured in what looks like a magical MRI, if he will agree to have a metal exoskeleton surgically attached to his body, giving him superhuman strength. With his enhanced abilities—and the help of a small crew including his friend Julio (Diego Luna)—he’ll bring down the craft returning Carlyle to Elysium and use a special chip to transfer the data in Carlyle’s brain to his own. That will give Spider the power to bring down the whole oppressive system by instantaneously making all humans—on earth as well as the station—legal citizens of Elysium.

But things go awry, of course, forcing Max on the run from Kruger, who takes Frey (Alice Braga), a nurse who was once Max’s childhood pal and is now a nurse anxious to get her terminally-ill daughter to the space station for treatment, captive. After some perfunctory fight sequences, that ultimately leads to a big showdown between Max and Kruger on Elysium, and to a supposedly happy finale in which a new era of equality for all is about to begin, though its realization requires some self-sacrifice.

Blomkamp gets some mileage out of the picture’s premise early on, particularly since the visuals—both on devastated earth and sleek Elysium—are impressive, even if, as is often the case in such futuristic material, they don’t reflect the vast advances in fashion and style that would undoubtedly occur over a century and a half. But when Max has the exoskeleton attached and becomes a man-robot hybrid, matters become much less interesting, especially since Copley doesn’t make Kruger anything more than a stock sadistic villain (much of whose dialogue is as unintelligible as Bane’s was in “The Dark Knight Rises,” though the problem here is his thick accent rather than a mask). When the two have their final face-off, it’s reminiscent of the sort of body-blow grunt-fests that Schwarzenegger specialized in—in early cheapies like “Commando.” And the addition of the damsel-in-distress motif involving Braga, who doesn’t bring much to the party, is no help.

At first Damon endows Max with a sense of geniality in gritty circumstances that’s mildly affecting, but after he’s turned into something akin to Robocop, he’s about as expressive as Peter Weller was playing that character. (One does, however, have to give him points for agreeing to have his head shaved for the part.) Foster is disappointingly one-note as Delacourt, bringing virtually no nuance to the role. Moura brings some skittishness to Spider that’s amusing if not terribly imaginative, and Luna manages a touch of pathos for the unfortunate Julio. But Fichtner appears to be trying to make up for his scenery-chewing as Cavendish in “The Lone Ranger” by making Carlyle as blandly uninteresting as possible.

On the technical side of “Elysium” is first-rate, with cinematography by Trent Opaloch that’s excellent except for some muddying in the fight sequences (the use of the Mexico City locations is exemplary), and the effects (supervised by Peter Muyzers) are exceptional, with Kruger’s facial reconstruction after being grotesquely disfigured by a bomb an especially cool moment, even though when so many people get literally blown up, the impact of body parts splattering into fragments begins to pale. Ryan Amon’s throbbing score adds excitement to the mix.

But ultimately for all its concern with the oppressed masses, “Elysium” has much less humanity to it than “District 9” did. The themes are the same, but the larger budget seems to have reduced Blomkamp’s ability to give them the dramatic impact they deserve. As usual, bigger isn’t necessarily better.