A terrifying vision of the whole wide world condensed into the body of a massive train barreling through a frozen post-apocalyptic wasteland, "Snowpiercer" excites, intimidates and astounds. Continually rejuvenating their premise with an inventive array of provocative ideas, writer-director Joon-ho Bong (2007's "The Host") and co-scribe Kelly Masterson (2007's "Before the Devil Knows You're Dead") have created a notable, particularly auspicious work within the science-fiction genre. Trickles of inspiration are undeniable—one character played by John Hurt (2014's "Only Lovers Left Alive") is even named Mr. Gilliam after one of the kings of dystopian satire, Terry Gilliam—but "Snowpiercer" has its own perspective on everything from class privilege and elistism to the brambly separation of caste systems. With everything boiled down into a single confining location, the picture comes to symbolize nothing less than a microcosm of modern human existence and experience.

In 2014, an artificial cooling substance called CW-7 was emitted into the upper level of the atmosphere in an attempt to head off the effects of global warming. The plan backfired, and the earth became an uninhabitable place blanketed by snow and ice. Seventeen years later, the last remaining survivors reside on the Ark, Wilford Industries' luxury locomotive cruise line joining railways worldwide. As their home chugs across harsh vistas bereft of life, the people packed into the tail—the lower class—are finally at the end of their ropes over the neglectful, emasculating treatment dished out by the entitled, abusive front passengers. When all of the children in the tail are cruelly snatched for reasons the adults do not yet know, it is the catalyst for a long-overdue uprising. Led by the brave Curtis (Chris Evans), assisted by drug-addled father Namgoong (Kang-ho Song) and teenage daughter Yona (Ah-sung Ko) who have the ability to unlock the doors, the group set out to ruthlessly overtake each successive train car as they move ever closer to the all-controlling engine in the nose.

Inspired by the French graphic novel "Le Transperceneige" by Jacques Lob, Benjamin Legrand and Jean-Marc Rochette, "Snowpiercer" is a rich, ravishing experience, a motion picture dripping in social consciousness and thematic intricacy without becoming preachy or losing sight of its other purpose as a rousing, robust entertainment. Striking with brutal force from the start, the film drops its audience into an uncompromising alternate reality that has been fully, in many ways staggeringly, conceived by director Joon-ho Bong and his exceptional team of technical artists. Controlled under the imposing, unfeeling thumb of the armed dictatorship onboard, the tail group—and, by extension, the viewers—are left outraged by their fate and circumstances. They know they are deserving of fair treatment, and their sacrificial journey to take down the sniveling bourgeois regime transforms the proceedings into a harrowing, bleakly humorous, breathlessly unsettling extravaganza of action and horror.

With each new door breached, Curtis, best friend and second in command Edgar (Jamie Bell), single mother Tanya (Octavia Spencer), and the rest of their self-imposed battalion are made privy to all the secrets of the Ark that have been hidden from them. Opening their eyes to a way of life the wealthy take for granted but some of their own have never known, they are essentially guided on a death-defying tour of how the other half—that is, the middle class and upper crust—live in contemporary society. In a hierarchy taken to extremes but still far too recognizable for comfort, the gun-toting oppressors wave their weapons around as a means of putting fear into the downtrodden. An elementary school classroom is lorded over by a perky, smiling teacher (Alison Pill) who brainwashes her students with songs about the filthy poor and the importance of keeping the engine running lest they otherwise all die horrible deaths. There are greenhouses, a dance club, pools, a lavish glass aquarium, and even a sushi bar—a far cry from the mysterious dark blocks of sludge the tail passengers are forced to eat as their every meal. As eye-opening as all this is for Curtis and his team to see, it is also equally hair-raising for people stepping foot into the unknown. Meanwhile, an artist stands back from the perilous melee, forever drawing pictures of each tableaux to which he is laying witness, Namgoong thinks nothing of lighting up one of the last two cigarettes in existence, and the sniveling, held-hostage Minister Mason (Tilda Swinton) begs for mercy with each new betrayal she commits.

Like his character of Curtis, Chris Evans (2014's "Captain America: The Winter Soldier") has grown into a natural leader, an actor of the weight, command and accessibility one looks for in an onscreen protagonist. Having been on the Ark for half his life—he is now 34—Curtis remembers what his existence was like before, and how the catastrophe altered his moral code in ways he didn't think possible. Evans effectively conveys the alternate rage and guilt of a man who acts with his physicality but tries to keep his emotions at bay. As Tanya, a battered-but-still-kicking soul willing to do whatever she must in order to get son Timmy (Marcanthonee Jon Reis) back, Octavia Spencer (2013's "Fruitvale Station") is seemingly incapable of striking a wrong note. It is a beautiful thing to see Spencer receiving so many meaty roles after years of being relegated to comedic side parts.

Ah-sung Ko (who previously worked with director Joon-ho Bong on "The Host"), as Yona, has an innate ability to express everything in a face that is at once fresh and wise. As a teacher who has probably lost her mind, Alison Pill (2012's "To Rome with Love") is unnervingly cheery for the five minutes she appears, proof that there are no small parts when they are as concisely written and fearlessly performed as this one. If the whole cast is entirely convincing, it is Tilda Swinton (2011's "We Need to Talk About Kevin") who is so plausibly, deliriously unique in her brilliant turn as Minister Mason that one cannot help but be glued to the sight of her every time she is in front of the camera. Despicable in her actions yet halfway sympathetic for how truly pathetic she is, Mason is a fascinating rarity to behold, brought to life with the sort of arresting, ethereal originality that only Swinton could bring to the role.

"Snowpiercer" feels colossal in scope despite its constricted setting, the locomotive's expansive interiors and material amenities beckoning the resilience and ugliness of a race of people who will do whatever it takes to retain, or reclaim, a certain manner of living. Moving at a breakneck pace, the film's blunt, bloody combat sequences bring momentum to the forward progression of the story without skimping on its characters and their personal plights and collective fights. Top-notch visual effects offer a breadth and tangibility to the frosty desolation outside the train's windows, while Stefan Kovacik's (2006's "The Illusionist") mesmerizing art direction and Kyung-pyo Hong's lustrous cinematography display a sharp contrast in portraying the tail's grimy squalor and the front's sleek, modern gleam. Disturbing in content but tautly suspenseful in form, the movie works extraordinarily well as one of the year's most jolting, satisfying action pics. Is the existence of a brain in its head the reason U.S. distributor The Weinstein Company delayed for months and then tried to bury its limited theatrical release? For a time, there was even talk of re-cutting the finished edit and adding a voiceover—an extraneous notion all the more ridiculous and insulting since its narrative is straightforward and not for one moment difficult to understand. Thank goodness saner minds prevailed, but no thanks to a studio that could have advertised and marketed the film as a summer blockbuster and gotten it the widespread attention it deserved. To watch the sardonic, ultimately empathetic "Snowpiercer" is to witness an illustrious sci-fi opus both blessedly intimate and buoyantly grandiose. So what if it is initially overlooked, done in by a miserable promotional campaign from out-of-touch Hollywood executives? When today's 3,000+-screen releases have come, made a few bucks and been all but forgotten, here is a work that will find its audience gradually, and stand the test of time.