The first couple of episodes didn't impress me, mostly because they were rushed (it is a web series) and I didn't particularly care for the FL. Understandably, she had a chip on her shoulder, but honestly, she'd had 18 years to get used to her destiny and do you really want to go your whole life hating everyone and have everyone hating you? But then, the show really started to grow on me. This is an enjoyable show to binge watch, as the episodes are short and there are only 12 episodes. This drama demonstrated that the living are often scarier than the dead; and that if you open yourself up a little to people, your burdens might be halved because you have someone to share them with. Everything was wrapped up nicely, though because of the short duration, there were questions that were left unanswered (mostly missing back stories), but I wasn't bothered by that. Honestly, even though they've confirmed a season 2, I don't really see the need for it, other than to see more of the actors' work.

Kim Sae Ron as Ga Doo Shim was very good in this role. She was able to convey the bitterness of her lot in life, yet with that vulnerability that, perhaps this time things will be different. This was a very physical role and she did a good job with that as well.
Nam Da Reum as Na Woo Soo. I've loved him in things he's been in so far. I think he did an okay job as the male lead here, mainly because it was short. I'm not saying that he's not ready for a lead in a longer drama, just that this was a good starting point for him.
Yoo Sun Ho as student ghost Hyun Soo. He brought a lot of life to the story, especially considering that he was a dead guy! He had a lot of humorous scenes, and when he played it straight, I really felt for him. I would have loved to have actually seen a scene with him resolving issues with his mother.
Bae Hae Seon as Hyo Shim (Doo Shim's mother) - she did an excellent job. She has a very lovely and calm demeanor, and she didn't play her character as over-the-top and cartoonish, as I was afraid she would. I would have loved to have seen more scenes of her and Doo Shim resolving some of their issues.

Writing - there were the typical high school drama issues: terrible parents, the pressure to be the top of your class (I thought the premise for the deaths was excellent - it was coming from a different angle), school bullies, the other girl that likes the ML and is mean and conniving. Every time I watch a high school drama, I think that there is no way I'd want to go to school in Korea! However, there were a few surprisingly swoony lines from the ML that I was VERY impressed with. Not only with the lines themselves, but with the way Nam Da Reum delivered them.

Music - to be perfectly honest, I don't remember the music. It wasn't out of place, but I wasn't impressed enough to notice any of it.

Rewatch value - I've got too many other things on my list.

Bottom line - if you've got a few hours, don't want anything long and drawn out, and would like to see something a little supernatural, give it a try!