So much about Snowpiercer goes a long way in placing it amongst the very best and smartest sci-fi movies around that any flaws prove to be glaring. What's not an issue is how Bong is able to fully realize a future world and all of its problems with a bare minimum of exposition, at least initially. Finally convinced of the threat of global warming, the world governments band together to release a substance called CW7 into the air. It works, but rather than dropping the temperature down a few degrees the world is thrust into a new Ice Age, killing all life on the planet but a handful of survivors. Somehow they all managed to board a luxury perpetual motion train known as the Snowpiercer, and now it races all around the world. If it stops everyone on board could die and humanity would be extinguished.
But that may happen anyway because the system aboard the train is divided up by social status. The dregs, society's poor, are banished to the train's tail while the elite live near the front in the lap of luxury. The downtrodden live in squalor, feasting on disgusting "protein" as their main sustenance, and suffering the wrath of train security if anyone steps out of line. There have been rebellions, all soundly defeated, but a new one is building led by the brooding hero, Curtis (Chris Evans), and his wizened old mentor, Gilliam (John Hurt). Tired of being bullied by the chittering, teeth-gnashing bureaucrat Mason (Tilda Swinton, in dork mode), Curtis, his right-hand man Edgar (Jamie Bell), and a drug-addled engineer (Song Kang-ho) gather an army and proceed to take the train car by car. 
Combining brutal action with art house sensibilities, think The Raidmeets Metropolis, as the tail section survivors endure one bloody battle after another against the elite's heavily armed goon squad. Bong and screenwriter Kelly Masterson aren't content to make this just another beat 'em up, though, adding in stark social commentary and a central mystery of the train's origins for audiences to ponder. Designed often like the levels in an arcade game, each train car has a different feel and significance, like the oddball classroom led by pregnant, gun-toting schoolteacher (Alison Pill); or one glorious car built as a giant aquarium. The amount Bong is able to accomplish on a modest $40M budget is remarkable and shows his range in capturing the vibrant and unbearably grim. Not that we should be surprised at Bong's range. This is the same guy who delivered one of the great modern monster movies inThe Host, and the haunting South Korean film noir, Mother, both exceptional entries to their respective genres. The CGI gets a little dicey when the action moves, however briefly, outside the train to the frozen Earth below. 
In working with a largely American audience Bong has managed to cull some memorable performances from his cast. Whatever the heck Swinton is doing with her nerdy librarian routine as Mason, she needs to keep doing it because she is simply amazing and a lot of fun. Supporting players Octavia Spencer, Ed Harris, Bell, Kang-ho, and Ko Ah-sung bring a ton of depth to characters that don't all get a lot of screen time. Evans shows off the physicality and stoic personality we've seen him employ as Captain America, but his character is probably the least defined of the bunch. That was probably done to maintain some level of secrecy but it becomes an issue later on we need to believe the choices he makes.
After a certain point the film begins to lose some of the momentum it left the station with as questions get answered and characters' true natures are revealed. This is probably the area where Weinstein was hoping to do some chopping as the final act is bogged down by a lot of people standing around explaining what was left out before. The energy comes to a dead halt as new surprises emerge seemingly out of nowhere with one major character twist lacking potency because of it. It's become a common complaint that Hollywood doesn't offer enough in the way of heady sci-fi movies but the truth is that dynamic is changing. In a way it's ironic that Snowpiercer isn't getting a wider release because it pulls no punches either in brains or brawn and should appeal to audiences of every stripe.
Rating: 3.5 out of 5
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