Saw this on Friday, and enjoyed it quote a bit.
So many of today's movies, especially the non-summer-blockbusters - phone in the end of the film, failing to add a plot twist or character development that would make you go "now that was good," instead having you leave the theater with the thought of "well that was okayyyyy, but for some reason I feel unsatisfied."
SnowPiercer definitely did not disappoint. The story line and characters continued to develop right through the end of the movie. There are certainly questions to ask, but I think that's okay to have one or two open questions at the end of the movie ("Perception" for example).
SPOILER ALERT!!!!!!!!!!!!!!
I will say that as I wrote this, I did think on the plot line a little more. The twists and turns were unique, but ultimately this was simply a remake of Logan's Run.