Watching this, quite a few things may confuse you. The story is not easy at all. It is about good and evil though. It is about how we perceive the world and what we make of it. It is about many things, a lot of you may experience and see, that the person next to you may not see.
The movie is made to be watched more than once. I had heard about the Wailing and how good it supposedly is - well now I can leave the supposedly part away. It is as good as people say it is. And it is another example of south korean filmmaking that not few see as a powerhouse in the world right now (some may argue it has been for quite some time now). This movie is another example for just that.
It is also a movie about prejudice, about how small our world is and how we react to an outside "influence". How things collapse and what society is capable of ... again so many things to discover here. Now that being said, it doesn't mean you will like the movie. Or that if you don't like it, it doesn't mean you have no taste in movies. That is the great thing about films. We all have different tastes and we all value things different. You may just want to see explosions. And that's more than fine. But it's not what you'll get here ... not for the weak hearted or squeamish just to be clear though ... this is brutal .. to watch!