The second “Hercules” movie of 2014 is better than the first. You might observe that that’s not hard, because Renny Harlin’s “The Legend of Hercules” with Kellan Lutz was absolutely atrocious. Expectations about Brett Ratner’s take on the ancient Greek hero with Dwayne Johnson were also lowered by the fact that the studio decided to keep it under wraps almost until opening day—never a good sign.

But against the odds “Hercules” emerges as a cheerfully unpretentious,mostly enjoyable throwback to the boys’ adventure movies of yesteryear. Despite some concessions to modern taste—including fiddling with standard mythology to make Herc’s parentage uncertain and explain away his gruesome role in the deaths of his wife and children (as well as the supernatural character of the various monsters he‘s said to have defeated)—it’s a fundamentally old-fashioned yarn, like one of Ray Harryhausen’s Dynamation efforts spruced up with better effects. Certainly it puts the two “Titans” remakes to shame, as well as recent reboot efforts like “Conan the Barbarian.” It has its flaws—the first of the two big battle sequences goes on awfully long, for example. But to compensate, Ratner and editors Mark Helfrich and Julia Wong bring the movie in at a mere 97 minutes, a virtual sprint compared to most of the bloated dinosaurs in the super-hero genre nowadays.

The script, derived by Ryan J. Condal and Evan Spiliotopoulos from the 2008 comic series “Hercules: The Thracian Wars” by Steve Moore, is a pretty simple affair. Hercules (Johnson), who’d accomplished most of his twelve famous labors for Athenian King Eurystheus (Joseph Fiennes), is tormented by the deaths of his family and has become the leader of a mercenary band that includes cynical Autolycus (Rufus Sewell), a childhood pal and ex-fellow soldier; Amazonian archer Atalanta (Ingrid Bolso Berdal); mute orphan Tydeus (Aksel Hennie); and wise but wise-cracking seer Amphiaraus (Ian McShane). Tagging along with them on their missions is Hercules’ nephew Iolaus (Reece Ritchie), an eager youngster who tells tales of his uncle’s celebrated exploits,

At the request of beautiful Eugenia (Rebecca Ferguson), the group takes on a new assignment: assisting her father, Lord Cots of Thrace (John Hurt), whose rule is endangered by an uprising led by the formidable Rhesus (Tobias Santelmann), a demonic figure whose troops include tattooed skinheads and, supposedly, centaurs as well. That involves transforming a ragtag group of farmers into a real fighting force and joining with Cotys’ general Sitacles (Peter Mullan) in leading it against Rhesus’ fearsome army. There follow two big battle sequences—the first in the close quarters of a devastated village and the second on a Thracian plain—which end with Herc and his allies victorious and Rhesus in chains. But since at that point only sixty minutes have elapsed, there must be a third act twist, predicated on the premise that in ancient Greek politics were even more duplicitous and nasty than there are nowadays, and that Hercules will have to conquer his own demons (in the modern psychological sense) to restore peace and order—with a little help from his friends, of course.

This “Hercules” differs from previous takes on the character—including Kevin Sorbo’s TV incarnation—in adding a dark side arising from his past. But it doesn’t dwell overmuch on that, except as the final hurdle he must overcome to defeat the villains against whom he has a private, as well as a public, grudge. (In this case, it will involve emulating Samson.) For the most part, Ratner’s picture avoids any sort of depth in favor of straight-on action storytelling. And it certainly doesn’t use elevated language in any effort to seem classical. (Any movie in which a villain not only orders his men to “Unleash the wolves”—the kraken apparently being unavailable—but later orders them to “Kill the dirty bastard!” could hardly be thought ultra-sophisticated.)

And that’s perfectly fine, because he tone the movie is aiming for an amusingly retro vibe that baby-boomers should immediately recognize from their youthful Saturday afternoon matinees. Even the effects, while far better than those of the fifties and sixties, are hardly cutting-edge by today’s standards: they’re cheerfully cheesy instead. The acting fits that mold, too. Johnson has grown increasingly loose and likable as his onscreen career has progressed, and makes a stalwart hero. He’s also surrounded by stellar support, with McShane and Hurt standing out, the former for his ability to toss off what passes for wit in this sort of picture with aplomb and the latter for his natural gravity. But Sewell, Mullan, Ritchie, Hennie, Berdal, and Ferguson also make solid contributions, and somehow having the lesser-known Fiennes brother play what becomes a pivotal part at the close seems a sly admission of the movie’s rather modest ambitions.

On the technical side, Dante Spinotti’s cinematography is first-rate, keeping the textures crisp even in the big battle scenes and making some nifty 3D points (as it swords and spears) without turning them into a crude fetish, while the production design by Jean-Vincent Puzos and the visual effects supervised by John Bruno and Dean Wright are more that serviceable. The same might be said of Fernando Valazquez’s energetic score.

In sum Ratner’s “Hercules” is dumb, old-fashioned fun of the sort one gets too rarely in popcorn movies today. Whether it can overcome general audience indifference to sword-and-sandal pictures is doubtful, but it deserves to.