It’s not often that a science fiction action epic like “Hope” finds itself competing for the Cannes Film Festival’s illustrious Palme d’Or. But such was the case for South Korean writer-director Na Hong-jin’s ambitious feature “Hope”. Of course it didn’t win, but its inclusion was a big step in getting the movie recognized. Neon ended up nabbing distribution rights and immediately put into motion a stateside theatrical release.

Few trailers have raised my expectations for a movie quite like this one. They teased us with exhilarating slices of the film, showing off tension-soaked action, the epic sci-fi scale, and some compelling mystery. Those things are all present in “Hope”. But sadly, the finished product doesn’t quite live up to Hong-jin’s lofty aspirations. He delivers a movie with plenty of cool ideas, most of which find their way on screen. But the frustrations set in as the film’s issues come more into focus.

Near the small town of Hope Harbor, police chief Ko Bum-seok (Hwang Jung-min) is called out to meet his second cousin Sung-ki (Zo In-sung) who has discovered a dead cow covered with massive claw marks. Sung-ki convinces Bum-seok the wounds are from a tiger. So the chief rushes back to Hope Harbor to warn the townsfolk of the danger while the headstrong Sung-ki and his hunting buddies track the dead cow’s demise to a nearby farm where they discover more carnage.

From there the majority of the story follows two separate but connected storylines. The first involves Bum-seok who returns to Hope Harbor only to find it in shambles. Most of the buildings lie in ruin and many of the people have been savagely killed. As Bum-seok investigates, he runs into several locals who frantically tell of a hideous monster rampaging through the city. He finally encounters the horrific creature and is almost killed. He ends up being rescued by a rookie cop named Sung-ae (Jung Ho-yeon).

Elsewhere, Sung-ki and his buddies continue to track what they believe to be the creature. The trail leads them deep into the forest where they find more carnage at a ravaged trappers camp. They quickly realize that they are not alone in the woods. And as they venture further they stumble upon some alarming truths that help bring the story’s mystery to light. But those truths come at a cost. And for them, it’s a brutal confrontation with the very thing they’ve been hunting.

The parallel storylines work really well, with both packing their own cool moments and big surprises. Each take their time revealing their otherworldly threats. And each comes with harrowing encounters, gruesome deaths, bizarre revelations, and pitch-black humor. Of course they inevitably converge for the film’s huge finish which does more to setup a sequel than tie-up any existing narrative threads.

But both storylines are also hindered by the same problems. They often take far too long to get where they’re going, overextending numerous scenes and wasting time on meaningless chatter and panic-driven potty-mouthed bickering. Also, numerous characters are noticeably underwritten and lacking depth, despite the movie’s hefty runtime. As for the CGI, it ranges from incredible to micro-budget awful. There are some wild tonal shifts, some shaky editing, and a final action sequence that is as endless as it is ridiculous.

Yet the most frustrating thing about “Hope” is that there is a truly great 100-minute movie somewhere inside of its overly long 156 minutes. Hong-jin treats us to some thrilling action, jaw-dropping set pieces, incredible production design, and some all-out gnarly moments (the alien autopsy scene is a grisly delight). But after a promising setup, the movie struggles to maintain its momentum and grows more repetitive the longer it goes. It’s an unfortunate result considering how great “Hope” can be when it’s hitting its marks.