Potentially a good movie gone woefully wrong: Snowpiercer

It's easy to make Snowpiercer sound like a good movie although it actually is not - it's nothing more than a cinematic cartoon or comic book (I would certainly guess that the source material is a comic), done with no style, characterization, wit, or surprise - just a lot of "action" which mainly consists of mayhem and ridiculously staged combat. The story: after some poorly explained environmental disaster that wipes out life on earth, a group of several hundred people are on a train (how they got there is never even discussed) that circles the planet again and again, maintaining the last vestiges of human life. The train is rigidly class divided, with the "lower" classes in the cars to the rear kept in prison-like conditions and the upper classes (white and blond) living in luxury and debauchery at the front of the train. Some 17 years into this predicament, the lower classes (black, dark haired, or Asian) rebel, fight their way to the front of the train, and at last confront the mysterious "conductor." Initially, I was hoping for a film with a least some of the intelligence of Battlestar Gallactica - the premise is similar in some ways - but where as BG was about real people and their attempts to maintain a civilized environment and to preserve human life, Snowpiercer is about two-dimensional cartoon characters and makes no attempt to seem realistic even by the broadest of scifi conventions. One another level, however, Snowpiercer is quite accurate, despite its bludgeoning technique: You can see this train as an analogy for our planet or or our society whether its First World v Third World or the Koch Brothers-Romney-et al. v the 47 percent: it's certainly true that we have come to accept a world and a society of extreme disparity and far too many have bought into the ideology that the wealthy deserve all that they've "earned" and that many or most of the poor have only themselves to blame for not taking advantage of opportunities offered them etc. Once that point is made, however, the movie goes nowhere with it and just hammers home the obvious - not aided at all by a ludicrous performance by Tilda Swinton, some totally bizarre ideas (people cutting off limbs and feeding their own bodies to the hungry to ward of cannibalism - huh?). Somewhere in this mess was potentially a good movie. This isn't it.