In fact, the series is good and with an open ending. Maybe one day they'll make a second season. PS: More or less in what year is the story set? Korea had a lot of wars.
That moment where you think you saved a child but it turns out the entire back of the train was full of zombies…
This is what it should have been from the beginning, not a silly series with boring jokes. If they took it seriously, they would easily have a Korean The Walking Dead.