I think the movie is kinda over-rated, in my personal opinion.
The plot is good, but I feel there are quite a few realistic loopholes. The build up and story plot is also average for me like 5-6/10.
This movie made me yawn quite alot of time.
Is not very captivating, ending is boring and no climax.
I don't think is worth 2 hours of the time.
Is a pity, because I like the Korean actors featured in this film.
Overall I will personally rate this movie a 5/10.