It was great if you hadn't read the Webtoon, which was very different. They changed and added major characters. I was confused when I saw some of them like ??? I don't remember that. Also, the order of events is very different from the Webtoon, as well as the wasy certain characters died, became monsters, or both. The thing that upset me the most was definetly the whole elevator part, it was very good in the comic and the reason for the shutters being down and them being locked in Green Home connected and made a lot of sense, but in the drama it did not. It was also kinda anticlimactic like man just kinda died?. (trying to avoid minor spoilers :)) I found it VERY upsetting that Jae Heon's part with the shield Du-sik had made (the one that was also a flame thrower) was not there and his "AND GOD SAID.. *flames spout from shield* LET THERE BE LIGHT", which was my favorite part in the series was not there. Overall, I was very sad that the events didn't match with the Webtoon and many things were different, if i hadn't read the Webtoon or known about it, I would have had no complaints. (Sorry for the horrible grammar its literally 1:34 AM and I'm too lazy to proofread)