My biggest issue was how unrealistic this whole plot was, and how it forced too many characters to act painfully stupid - this stopped me from getting immersed into the story and caring for the characters.

The setting is truly interesting and allows you to slowly build the atmosphere. The dark tunnels, small spaces - all anxiety inducing. You could potentially feel the disorientation of the characters, when they are being chased by the killer. Sadly, I could not feel it. Why?

With the number of victims, the police reaction, or rather the lack of reaction, was quite ridiculous. It would be better to not involve the police at all, and make me wonder where they are when needed, than make me suffer watching this level of incompetence and lack of care.

I can deal with one stupid character… maybe two. But all of them? That’s just a pain for my brain. I get it, if everyone is smart, the movie ends before it starts. Just write a smart villain with a realistic setting that does not need characters with two brain cells to make it work.

Was the villain part of some supernatural evil gang? He was undestructable. I feel like one could cut his head off, and he would go: day like any other.

So, what’s good? Amazing performance. It’s Jung Kyung Ho we’re talking about. I am 100% certain he can sell literally any role and make it good. I also really liked Choi Deok Moon as Jong Ho, one of the victim’s father. Yun Seo had some clever tricks and moves, so it was truly entertaining to watch her navigate this deadly underground labyrinth.

Overall, good suspense, good visuals, great idea - if only they lowered the number of initial victims and kept the police away from it. Make it only a story of Yun Seo, Soo Jung and Jong Ho, and I would love it.