Wow!! I loved this drama so much!!
Please note, I did not look at the webtoon, I didn't even know about it. I'm fresh eyes.

Acting: The acting was absolutely perfect! Every actor/actress did their role so well, I felt every emotion and could really step into their shoes.

Story: The story, overall, is really good! I was hooked. My eyes were basically glued to the screen, and at some moments, I actually had my eyes wide open, while grasping my mouth in shock.
The theme of monsters VS humans is really intriguing, because of the way this movie took it. It's not just "bad monsters" vs "good guys". It goes soooo much deeper than that. I absolutely love that dynamic.
Some characters are well-developed. Some art not. But the most important ones-- you can clearly see the changes.
I do have to say, though, that some parts are not explained fully clearly enough, and were so sudden/out there, that I often had to rewind a bit.

Music: LOL I don't know who picked the music, but honestly, some of the music was really random/out of place, and did not fit the scene at all. It felt like I was watching a normal quiet movie scene, but some kid was playing music near me.

Effects: I LOVE the special effects, makeup, ALL OF IT!!! Wow!!! Especially one creepy scene in episode 10, I replayed it, because it was so EPIC and so dang aesthetic. As an artist, I was screaming!