For a movie that had so much promise, it completely missed the mark. However, I must say the actors/actresses did a stellar job.
Inconsistency and breaks in logic throughout the film. In some cases, actions in the past only affect Seo-yeon, in other cases it affects everyone, how they are correlated doesn’t always make sense. This is my personal opinion but I feel the plot flip-flopped wayyyy too much. The whole death-disappearance thing is also inconsistent throughout the film!
TLDR; great performances, poor storyline.