I enjoyed the movie, but I can only say that everything about it is just "alright". The concept is interesting, the characters have personality despite some of them having minimal screen time, the camera work is pretty, the CGI is good enough, and the only aspect I found somewhat lacking was sound design. It's clearly very artistic and there are some scenes with a great focus on it, but I couldn't help but find it just ever so slightly awkward. There is however one single moment (involving a slap in case you wanna know which one I'm talking about) which used sound in a very organic and pleasing way.
My main peeve with the movie is an unclarity with what the tone of the movie is supposed to be. The movie is dramatic, brutal, scary, and absolutely horrifying in some scenes, yet it still takes shots at comedy, which end up coming off as absurd, in poor taste, and simply don't fit in with the tone of the scene and let alone the movie. The next paragraph will talk about one of these moments, so skip the next paragraph if you don't want a medium spoiler.
During a big fight with a whole train car full of terrifying masked soldiers armed with melee weapons, the most brutal, bloody, and visceral fight of the movie, where lots of poeople lose their lives, the battle it suddenly stopped when one of the managers of the train enters the car. She announces it's new year, everyone holds their weapons in the air and shouts "happy new year", and then carries on fighting. Like, what the hell is that supposed to mean?
I recommend the movie to everyone, but I have to say that it was slightly sub-par, and many things could've been much better.