Post apocalyptic Seoul. Directed by Taehwa Um who wrote the script based on a "webtoon" by Lee Shin-ji and Kim Soong-nyung (says IMDB).
I guess the first apocalypse was the urbanisation of Korea, with the bulk of the population living in apartments that are heavily stratified by class, wealth, etc. as explored at feature length in Parasite (2019) (amongst others) and summarised in a rueful intro here. The second is a massive earthquake that levels the city with the singular exception of a block where young couple Park Bo-young and Park Seo-jono reside. A third takes the form of eventual "delegate" leader Lee Byung-hun (OK but far better in No Other Choice (2025)) who happens to be settling a score there that day and so survives while his wife and child do not.
Things go tediously predictably: Korean Lord of the Flies (1954). The initial mildly amusing black social comedy quickly yields to unfunny repetition and shouty histrionics with too many overlong scenes that canvas some but not all of the things that happen when infrastructure fails. Soon enough it's a boring slog.
A Critic's Pick by Jeannette Catsoulis. "Smoothly shap[ed] familiar genre tropes into a brutal study of class warfare and the stifling of pity".
