It’s so easy to be glib in dismissing summer blockbusters: They’ve gotten too big, too loud, too dependent on slick computer effects and too dismissive of fusty ideas like narrative and character arc. How depressing the routine has become, watching otherwise gifted stars squander their talents on the altar of the lowest common denominator.

Then, something like “Edge of Tomorrow” comes along, and it looks like there’s still hope. A crafty, clever, stylish science-fiction action ad­ven­ture, this time-travel loop-de-loop didn’t have to be this good. But thanks to the efforts of a superb creative team and Tom Cruise — here deploying his own persona with stunning self-awareness and humor — what might have been a throwaway genre exercise instead turns out to be a surprisingly satisfying day-after-day-after-day at the movies.

Synopsis is not our friend when it comes to summing up “Edge of Tomorrow,” whose title was mercifully changed from the dreadful “All You Need Is Kill” (the name of the Japanese novel it’s based on). Cruise plays Maj. William Cage, a media relations officer with the U.S. Army of the very near future, when Europe has been overrun with an alien force of huge, hissing, squid-like dervishes. When Cage is unexpectedly drafted into a platoon readying to invade France, he blanches: He’s a coward, all too ready to use his disarming grin and ad-man charms to get out of any real danger.

Instead, Cage is plopped down at Forward Operating Base Heathrow in London, where he’s outfitted with a computerized exoskeleton that turns him into a rock ’em, sock ’em robot. Also training at the base is a world-famous special forces soldier named Rita Vrataski (Emily Blunt), known as the Angel of Verdun for her heroics at that eponymous alien battle. The two eventually cross paths, with Cage being tossed into a repetitive and deadly time loop that resembles a cross between “Groundhog Day,” “Saving Private Ryan” and Wile E. Coyote’s worst morning ever.

If that last reference suggests a note of antic physical humor, that’s because “Edge of Tomorrow,” which has been brilliantly adapted by brothers Jez and John-Henry Butterworth and Christopher McQuarrie, pops with moments of welcome, unexpected levity. This especially comes through when Cage begins to grok what’s happening to him and starts to riff and rush along encounters that he’s been through dozens of times before.

Aided by the crackerjack cutting prowess of editor James Herbert, director Doug Liman skillfully conveys the endless repetition without making “Edge of Tomorrow” repetitive itself. He quickly, and often amusingly, cuts to the chase of each sequence, during each of which Cage tries to nudge reality just a bit further in the direction of survival and saving the world before he dies and has to start all over again.

As light as “Edge of Tomorrow” is on its feet, it still manages to balance that fleetness with visceral, impressively staged battle sequences. Borrowing nomenclature and visual language from classic World War II films, the film re-imagines D-Day as a high-tech aerial assault on Normandy, with terrifying tentacled creatures rising out of the waters and flaming shards of planes crashing down on their own human cargo. The tableau is gruesome and intense, with Cage initially a passive, horrified victim and then, eventually, an agent in a carefully ritualized study in fate, human nature and the possibility of growth and change.

Like the classic war films it lovingly quotes, “Edge of Tomorrow” even has a ragtag group of misfits, in this case the battle-scarred squad that Cage is thrown into over and over again by his drawling master sergeant, played with a barely dis­cern­ible wink by Bill Paxton. (When Cage notes from his Southern accent that he’s obviously American, Paxton flawlessly barks back, “No, sir, I’m from Kentucky!”)

But the centerpiece of “Edge of Tomorrow” is the burgeoning relationship between Cage and Rita, whom Blunt invests with just the right mix of machisma and soulfulness. (Between this, “The Adjustment Bureau” and “Looper,” she’s apparently the go-to girl when it comes to busting the time-space continuum.)

Even with Blunt charismatically holding her own, the undisputed star of “Edge of Tomorrow” is Cruise, who, as the story’s reluctant hero, delivers a one-man master class in his own fascinatingly protean screen presence. Starting out as a shallow, cocksure sharpie “Jerry Maguire” — even sporting some “Risky Business” baby fat — he smoothly navigates the myriad tiny transformations that Cage goes through, until he becomes the flinty, competent, steely-eyed saver-of-the-day that his “Mission: Impossible” years have taught us to expect.

What’s more, he earns every beat in a performance that calls on him to undergo all manner of physical punishments and slapstick indignities. Like summer movies themselves, it’s become so easy to be glib in dismissing Tom Cruise. “Edge of Tomorrow” provides welcome and hugely entertaining evidence that he’s still a star of considerable gifts, and savvy enough not to let them be squandered just yet.

★ ★ ★

PG-13. At area theaters. Contains intense sequences of sci-fi action and violence, language and brief suggestive material.

113 minutes.