The potential was there, but this KBL has the typical issues you know from other KBLs. It's too short and therefore lacks depth and feels rushed. The story itself wasn't that bad, but the love between the two characters developed too quickly (which wouldn't be a problem if the couple had insane chemistry to make up for it). The central conflict fell flat. The acting was also lacking. There was no noticeable/outstanding chemistry between the two leads. Many scenes felt stiff and awkward. For a BL to be enjoyable (IMO), it has to fulfill at least two of the following things:
1) captivating/interesting story
2) chemistry between the characters (platonic and romantic)
3) good acting

The premise was that Jun Ho was trying to make Min Hyun fall in love with him so he could drink his blood and not die from the curse (?). But I didn't feel the tension or the heaviness of the situation when Min Hyun fell for Jun Ho. I didn't feel the inner turmoil of Jun Ho when he fell for Min Hyun and had to decide whether he should kill the boy he likes to survive or let him live and give up on life. The worldbuilding was very shallow. Nothing is explained (like the whole pureblood thing) or the curse. It's all very shallow, and I guess you could argue that this show has less than 90 minutes of runtime, but so do many movies, and even they manage to make the most out of it.

You could say that the CGI-vampire-eyes aren't done well, and I guess I'd have to agree. Still, just like in Color Rush, I think it has a certain charm (even though I don't understand why they decided to make the vampire eyes red and green without any information or explanation - surface-level worldbuilding, hello).

Another point that made me lower my rating was the ending. It wasn't satisfying or a reasonable conclusion for the story. It felt empty (to me). BUT not everything was awful. I think that there are probably many people who will enjoy this show. I thought it was an easy and quick watch; it just wasn't my cup of tea.

Min Hyun found out the truth about Jun Ho pretty quickly and was just okay with it. Also, the guy he fell for wanted to use and then kill him was not a deal-breaker for him. Therefore, I didn't care either. Min Hyun kept begging Jun Ho to drink his blood; Jun Ho refused, Jun Ho died. The brother who was supposed to be an obstacle was never brought up again. The principal lady, who was apparently Jun Ho's friend (?), didn't do anything significant either.

I'm not super opposed to sad endings or major character deaths if they are done well. Ending your show with one of your main characters dead and just leaving the whole show on a sad note should be handled carefully. In this case, Jun Ho's death wasn't impacting me the way it should have. If that was because I wasn't super invested in the characters and the story anymore or because of the acting or directing, I don't know. One thing that played into my apathy towards the ending was that Jun Ho seemed like he accepted his fate and was not afraid of dying or fighting to stay alive. Therefore, I wasn't feeling sad that he had lost his life. Like yeah, it's unfortunate that he and his love were separated, but they knew each other for like what? Ten days? Three weeks? Six months? (the time span is also very vague, and one can only guess) I didn't expect this show to have a Twilightesque scene where Jun Ho ultimately decides to suck Min Hyun's blood and has to stop himself before he kills him, but I guess that I would've expected... more.