South Korean director Bong Joon-ho tale of post-apocalyptic insurrection, “Snowpiercer,” arrives in the states on the heels of a minor controversy, after domestic distributor and notable meddler Harvey Weinstein famously attempted to wrestle final cut of the film away from Bong and edit it down for purposes of length and pacing.  Bong fought back in a public dispute and won, maintaining final cut of the film.  Much has been made of Bong’s bravery for going head-to-head with one of Hollywood’s most ruthless titans.  But having seen the film for myself, I wonder if maybe Weinstein was right to interfere: “Snowpiercer” is a glorious mess, a visual feast with a terrific conceit that ultimately loses its way in tone and momentum.

The movie opens nearly two decades after the world’s nations tried to reverse the effects of global warming by launching a cooling chemical into the atmosphere.  The plan backfired, the earth froze, and nearly every living thing on the planet died.  The few lucky survivors horded themselves onto a technologically advanced train that endlessly circles the earth, and now live according to the divisions of class, with the poorest of the lot sardined in the shadowed confines of the rear car, while the wealthiest live up front in style.  No one in the back has ever been up front, and vice versa, owing to a team of heavily armed combat troops that seem to patrol the areas in between.

Curtis (Chris Evans) remembers what life on earth was like, having spent half his life there before the frost.  After seventeen years aboard the train, he despairs of being part of the one percent shoveled in the back in cramped quarters without benefit of a shower or clean clothes, and forced to feed on gelatinous blocks of black protein.  But all of that is about to change: Curtis, along with his angsty sidekick, Edgar (Jamie Bell), who was born on the train, and the wizened sage, Giliam (John Hurt), is planning a revolt.  The plan seems simple enough, if not easily executable: once a day, all the doors between the cars are open for exactly four seconds simultaneously.  All they need to do is block the doors, rush the guards, and storm the front.  Control the engine, Gilliam reasons, and you control the train.  Of course, things don’t go off as planned, otherwise this would be a very short film.

The first attempt meets with disaster—and the very disturbing ire of Mason (Tilda Swinton), the front-car liaison.  Mason is an acolyte of the unseen Wilford,  Keeper of the Sacred Engine, who, legend says, created the train and saved all these wretches from certain death.  She extolls the virtues of separating the classes and maintaining order as a means to keep the train alive, before ordering a mass execution of the poor as punishment for their insurgency.

Got that so far?  The middle act of the film involves the downtrodden taking on the establishment to penetrate The Sacred Engine, which basically involves a series of three or four violent set pieces where scores of people are slashed, shot, stabbed, impaled, beheaded and generally eviscerated.  For the most part, these scenes work, as Bong steps into his comfort zone of highly-stylized action, a trademark of South Korean thrillers.  The set designs and cinematography are a wonder, too, as Curtis and his group of ragtag misfits move from one car to the next, understanding the degree to which they’ve been deprived of simple pleasures with every step.  Each successive segment gets lighter and brighter, in a gradation not only of color, but symbols of wealth and status: entire cars are filled with hydroponic crops of fruits and vegetables, animal farms, and cold freezers hung with every meat known to man.  There’s a sauna and a steam room, a first-class lounge, and even a classroom overlorded by an unhinged teacher who has taught the train’s wealthiest children the finer points of discrimination.

What happens to the rebels, I’ll leave for you to discover.  The movie’s final scenes are strong, as Curtis comes to understand his small place in the microcosm of the train and humanity, at large.  But it’s everything in between the finale and the actions scenes that fails.  I said in the beginning that the movie loses its way, and so it does.  The reasons are largely intangible; it’s just a feeling I had while watching the film that perhaps Bong had lost some connection with his source material.  “Snowpiercer” seems like it was probably a decent prospect on paper, but Bong’s vision can’t manage to place it firmly in any one territory.  There are moments of black comedy that shift uncomfortably to violent action and back to black comedy again, before segueing into overwrought melodrama that drags the movie down.  Curtis’s scene of painful memory recall to his first days on the train comes across as forced and disingenuous when it should be powerful.   And the countless metaphors about social inequality are blunt and heavy-handed, although this is more the fault of the screenplay than anything else.

I dunno.  I’m praising “Snowpiercer” for its finely-honed action sequences and visual acuity, and think you should see it based solely on that.  But I’m warning you that the movie is not quite the sensation critics have made it out to be.  Perhaps movie audiences have been so starved for original material that they’re thrilled to latch onto anything that doesn’t involve sequels or comic book heroes.  Perhaps, too, more thoughtful independent film buffs have been aching to finally throw their support behind the little guy who managed to take down the big guy in the form of Bong vs. Weinstein.  After all, it was a cause not unlike Curtis’s, and everyone loves an underdog.