You know those movies where workers on an oil rig are attacked by a monster like The Rig, The Thing Below or Parasite? Well, this is one of those only with Koreans.
It's a passable example of that particular subgenre. The cast is perfectly fine. Ha Ji-Won is fairly convincing as a hardass oil rig worker. She's more convincing than a lot of these hardass female characters are anyway. The CGI is not great but it's serviceable though there's a green screen sequence late in the movie that is laughably bad. The plot is pretty generic but not more so than a lot of these things. The final battle with the monster is okay but it goes on way too long and starts to drag. My attention started to wander towards the end because it went on for so long. It eventually ends. It avoids the lame stinger ending that most of these have. I gave it a couple of points just for that.