I can't believe I haven't heard of this movie earlier. This movie should have more fame than it has now. As the name suggests this movie is just first part of a bigger story with a second part on the way this year. But the story, production quality, acting and the action scenes this movie offers is simply mind blowing.
The movie starts out slow but it ends with a bang. I haven't seen such good quality actions sequences in many Korean dramas or movies. It even beats majority of Hollywood action movies in regards of action sequence. I rewatched the second half of the movie just for the action.
The story delves into dark corners of scientific research and the movie has supernatural elements to it and contrary to my expectations it didn't actually ruin the movie but actually enhanced certain parts of the delivery of the movie. It has some gore to it but it's not too much.
The cast and acting was also very very well done with Choi Woo Shik being placed in a character that's very unusual for him at first glance but the result being a pure success. Kim Da Mi's acting in the 2nd half was also very impressive and helped build the overall atmosphere of the movie.
They used some old school korean music in this movie which I really liked as you don't really hear them in the average movies and dramas these days and it was quite nice.
If you are into action thriller movies then I would definitely recommend it.