I'm not someone that likes action that much, nor do I like gore, but this series deserves a good review.

Things that especially deserve praise:
First of all, the fighting sequences were top class ? amazingly executed, they'll keep you on edge. You just cannot deny how good those scenes were.
Second, the acting. The main leads were amazing, the bromance between them was very natural. The actor that plays Geonhoo has such delicate expressions, you can see the happiness, fear, anger, passion – everything clearly in his eyes. The other actors were good too.

Things that I personally don't like:
1. Quite a lot of gore. Sometimes it even felt like it was too much for no reason lol like they even showed little things like drawing blood during a blood donation very graphically. And obviously everything else was much worse, I couldn't watch. So yeah very graphic display of blood and injuries, be warned.
2. Since this isn't a favoured genre of mine, I was pretty distracted during most of the discussion scenes. I'm not very good at paying attention to those long serious talks and discussion of plans by the good guys and the bad guys. And there's quite a lot of that in this series so I was often lost on the plot and just let myself figure out what's going on as it went on. I actually thought I wouldn't like this series for that reason, but the story and acting kept me hooked later on.

It's not a series that one would re-watch though, although I can see people rewatching just the fighting scenes haha