“The Great Flood” possessed the potential to become the most impressive disaster movie I’ve encountered, and in some respects, it manages to live up to that promise. The film effectively combines the familiar, albeit imperfect, routines of suburban existence with a progressively frightening catastrophe. It begins gradually, featuring persistent rainfall, but then shows water rising to immense heights outside South Korean apartment buildings, culminating in enormous waves that destroy any sense of security and predictability. Considering it this way, the movie is truly remarkable. The cast delivers excellent performances—restrained yet emotionally impactful. As another critic noted, the film’s weakness lies in its divergence from the original storyline. It attempts to present a philosophical exploration of morality and humanism during its latter portion, but falls short of fully realizing that aim. The central issue is the abrupt shift in narrative direction isn't prepared for or presented clearly. One could also suggest that the same emotional impact might have been achieved by expanding on the initial premise it so powerfully established. Ultimately, "The Great Flood" feels like two separate films. The first half is exceptional; however, the second half obscures its intended meaning regarding what it means to be human—a message it was already effectively conveying.

Source on TMDB