I have read this webtoon a long time ago and as I was watching it was actually adapted scene by scene from the comics. This series made me use my phone for over 9 hours because I couldn't stop after seeing the cliffhangers in every episodes. I would say thanks to netflix!
I love the acting! I'm a big fan of Song Kang and Lee dong Hyun and I can say that they improved their acting a lot.
CGI was nicely done although it's pretty obvious that the monsters are computerized it wouldn't take away the fun.
The music was thrilling which made watching more fun. It was lip and thumb biting.
I would definitely watch this again in coming years or before season 2 comes out! (If there will be ;))