This is a straight forward exorcism movie, with absolutely nothing new for the genre, the exact same formula but with the typical Asian twist that you will easily see it coming in the last act.
Sadly to say, I did not enjoy it, it felt overlong, boring and a tad bit all over the place, especially the first part. Surely enough, it takes its time to properly start, even tho it is quite clear what the movie is about, and then it just goes over and over the same things every single possession movie did so before.
It was rather hard for me to keep my interest going, but nevertheless I can definitely say that Byeonshin is a difficult movie to watch, simply because it tries too much in a area that has so little to offer. We all have seen this many times before and simply because it is Asian and does not involve a ghost with long dark hair, does not mean that different is good. It was quite a challenge to stay in focus with its development.
Cheers!