His latest, "Hope," is his biggest and wildest movie yet. But despite its heft in scale and run time, it rarely pauses to take a breath.

Though some of Na's contemporaries are better known in the West, the South Korean writer-director has for two decades been a must-see filmmaker for breathless spectacles laced with pointed satire and scruffy humanity. His appropriately titled 2008 debut, "The Chaser," focused on a pimp and former police officer trying to find a missing sex worker in a helter-skelter search through nocturnal Seoul.

Since then, the headlong pursuits of Na have grown more expansive and extreme. A gambling-addicted taxi driver on the run (2010's "The Yellow Sea"). A police officer hunting down the cause of a disease outbreak in rural Korea (2016's "The Wailing").

The scope of "Hope," his first film in a decade, is so vast that Na spent two years in post-production toiling over it before premiering it at the Cannes Film Festival in May — in a slightly different cut than is now arriving in theaters. As if a 156-minute run time wasn't enough, it was also made with a sequel in mind.

But through those two and a half-plus hours, "Hope" hurtles its way through genres the way the Kool-Aid Man crashed through walls. It is not always a smooth ride. The CGI in "Hope" won't win any awards. And the movie is overlong, sapping some of its momentum. But it is often thrillingly shape-shifting: a gloriously unwieldy spectacle that fuses monster movie and science fiction into a blistering and bonkers saga of otherness — human and otherwise.

Signs reading "Protect the nation against infiltration" can be seen in the town of Hope Harbor on the South Korean side of the Demilitarized Zone. There, the local police chief Bum-seok (Hwang Jung-min) is investigating a mysterious animal attack. The best guess of a group of hunters led by Sung-ki (Zo In-Sung) is that a tiger has made it through barbed wire fields from North Korea.

Bum-seok, though, is soon on the trail of something evidently much larger and more destructive than a loose tiger. Long before he — or we — get a look at what's running amok, he chases through the rubble wake with increasing trepidation. Expletives make up almost all his breathless dialogue.

It will be almost an hour before we get a look at what he's after. Once we do, it's a bit of a letdown. The CGI makeup of the creature — a towering but lean and sinewy alien that sometimes stands tall and sometimes runs on all fours (played in motion capture by Cameron Britton) — is a little schlocky in design. But it's telling that Na's movie turns on a slow-motion close-up, when Bum-seok recognizes something like pain in the eyes of the marauding monster.

Na's movies have never been particularly kind to the authorities; they're usually shown as either incompetent or corrupt. In "Hope," they're mostly bumbling or way out of their depth. But Bum-seok is at least charging forward, albeit not with as much panache as his fellow officer Sung-ae (Hoyeon). She joins the chase midway, elegantly speeding into the fray in a squad car while shooting out the window. This is the big-screen debut of Hoyeon, of "Squid Game," and, from the very first moment, she's winning.

After the chase — which runs for the better part of an hour — Bum-seok and Sung-ae begin trying to investigate what they've encountered. It's probably the baggiest part of the film but it's also when Na is at his most mischievous. There is, for example, the medical examination of the alien's corpse, carried out not with calm precision but with a chain saw. And then there's the unforgettable eyewitness account of a villager who's seen the aliens in the forest — while terrified, crouching in hiding and trying to hold back diarrhea. In vain, it turns out.

You could chalk up such digressions in "Hope" to the devilish hijinks of Na. But they also reflect Na's insistence on making a human-scaled movie — a funny, farcical, ridiculous one — even in increasingly sci-fi extremes. That sensibility makes "Hope," shot handsomely by cinematographer Hong Kyung-pyo ("Parasite," "Burning"), very much its own, unpredictable thing despite its familiar genre setup.

The film, meanwhile, shifts to the separate, ongoing search in the woods by Sung-ki and the hunters. There, we learn more about the extraterrestrial visitors. In a cross-species leap of empathy, "Hope" begins shifting to their perspective, too. The leading figures are played by a trio of Hollywood stars (Michael Fassbender, Alicia Vikander, Taylor Russell) though they're unrecognizable under so much CGI-rendered alien skin. Well into the movie, their sounds get subtitles of their own, and the empathy of "Hope" begins stretching into the cosmos.

Whether Na's film, said to be the most expensive Korean film ever made, gets a follow-up remains to be seen. But for now, we get the movie's grand, galloping finale. Up until then, "Hope" is mostly a cluttered film. Production designer Lee Hwok-young delights in the debris of destruction. Yet "Hope" clears out for a sensational, open-road, wide-expanse chase scene that's one of the most exhilarating and ludicrous sequence of the year. Should Na continue this saga? That final sequence has you hoping.

"Hope," a Neon release in theaters Friday, is rated R by the Motion Picture Association for strong bloody violent content and language throughout. In Korean with English subtitles. Running time: 156 minutes. Three stars out of four.