The degree of terror is not inferior to "A trip to Busan". Is the plot of the movie Snow Country Train sentimental?

The movie Snow Country Train tells the story that the outside world is frozen and people can't survive at all. The only survivors are the people on the train. However, the people on the train are very solid. People in the first-class car enjoy food, medical care, education and entertainment, while people in the last-class car have a hard life and can only eat food made by cockroaches, so they have resistance. The whole movie is a rebellion of the people in the last carriage.