To start off, I'm not a fan of horror but I didn't find Monstrous particularly scary. There are a few moments that could be considered jump-scares, but the drama didn't really rely on these for shock value which I appreciate. There are some creepy elements though.

I really liked that each episode was ~30 minutes long. It helped the story move along, but at the same time it didn't feel like it was progressing that much either. Each episode felt similar.

The story isn't anything new nor special. They try to explain how the curse works, but it's a bit glossed over and confusing. Also, I felt like it was more about the family of the lead characters than the mystery / curse.

I thought that Shin Hyunbin would've played a bigger role, so that was a bit disappointing. She still acted well, as did the other actors - solid acting all around from the cast. Personally, I enjoyed Nam Dareum's performance and his character's relationships with his mother and Kwak Doyeon's character, though their story feels very short despite the history of their friendship being shown.

The series could've done more considering they had some great talent. Overall, it's just okay - still enjoyable.