I only stumbled upon it when browsing through Viki and decided to jump in since it was nearly finished. Thankfully, I had no expectations for it ahead of time and that paid off. I expected thriller/suspense but after the first episode, it was clear what they were going for. If you get easily scared and like thrills, you'll love this.

The cast looks really great, but I must say the acting for most were pretty mediocre. I wasn't convinced by anyone of them, apart from Lee Jun-seong. He did a pretty decent job.

For me, it works as background noise and I found myself fast forwarding a lot. Not the worst I've seen, not the worst either.

[spoiler] The action scenes themselves were ridicilous. Especially the shootouts inside of the bunker near the end. you stand two meter apart, blast off with full auto and miss a target straight ahead of you? I lol'ed. It was so bad it became hillarious. [/spoiler]