There are a lot of very interesting themes in the story though, the action is well done, the production quality is high, and the movie pays homage in tone and style to other great movies. When a movie's technobabble is terrible, it helps to pretend it's fantasy. If you don't and you let bad science get you down you could miss out on the other parts.
That said, it is very well produced and if you can set aside the technology aspect of it I would say it's among the better sci-fi movies in recent memory.
Turgid nonsense. I couldn't watch past the first half hour. If I'd paid to see that at the movies I'd have been properly angry.
I came away from it thinking that if I hadn't read the Silo Saga, I might possibly have actually enjoyed Snowpiercer, though definitely nowhere near 95%'s worth.
There were a LOT of copied ideas. Perhaps none of them were original to Wool, but Wool was not (to my knowledge) as much a clone of any individual work as it was the compilation of a lot of tropes.
The point is though that this is a question of taste. Maybe my tastes simply aren't aligned with what a lot of other people like. But it is for that reason that I simply don't trust RT. For many things I used to use Ebert, since I could usually predict from his review wether I'd like it.
(I havent looked closely but I do wonder if selection bias impacts review sites. If a limited appeal movie comes out, and the mainstream reviewers ignore it, and all the reviewers that RT aggregates are from the world that the move does appeal to, does it end up scoring much better than if all the mainstream usual suspects had reviewed it.)
There's also arguments to be made about the philosophical message of Snowpiercer, but I don't think that's particularly relevant to why the movie is great (though obviously others disagree).
Though maybe I was blinded by the nonsense, to a wonderland of interesting screencraft. But I don't think so.