OK, so...

~~Story~~ Interesting concept about a being that is not overused in other shows (even though most fantasy beings share the same traits such as immortality, mind-reading, etc). The fantasy elements fit right in - no need for that many visual effects. The first few episodes (1-6) are extremely binge-able as we get lots of new information and interesting interactions. Things get rather slow-paced and dramatic afterward. Even though I was expecting more emotional and memorable last 2 episodes, I still think the ending was OK and gave us a clear explanation. I presume that most viewers will feel kind of disappointed if they compare the first and the second half of the drama though, as the tone and pace of the story changes a bit. There are some confusing parts regarding the "contract", which made the overall story a bit weak IMO. Also, the second leads' story was a bit meh, not really to my taste with all that "coulda-woulda-shoulda" shenanigans. Maybe it's just a personal preference, but still. They were cute though! :D

~~Cast~~ GREAT CAST! A lot of actors I'm a fan of, and they did not disappoint. Especially the main leads <3 Unfortunately I think the script itself was weak in some of the scenes, so I'm not sure if I didn't like the acting itself, or just the dialogues, but second leads were not as convincing as the main leads, in my opinion. But overall the acting was very good/convincing!

~~Music~~ The OST is seriously one of the best parts of this drama. Very emotional and beautiful!

~~Rewatch Value~~ Well, I kind of want to rewatch the first 6 episodes, not gonna lie. The rom-com part is strong there and it's just interesting to see how the main leads fall in love. However, as the drama progresses slower in the second half, we don't get as much action, it's just the feelings sink in deeper. I guess if you like the melodrama and tears you would love to rewatch the whole thing, but it's not for me. Once I know the ending, I'm all for the rom-com/exciting parts :D