I just finished the movie a little while ago and I'm still thinking about the characters.
I was so invested that my eyes were glued to the screen!! I felt tense, scared, and angry, so I'd say it's a good movie because it managed to convey such emotions to me.

The actors did a great job and it was the first time I saw Kim Nam-gil and Lee Byung-hun acting!

But some negative points I have are: Im Siwan's character died so quickly ? I wish he had more screen time. I felt that the ending was very rushed, they could have shown the reunion of the survivors with their families and the recovery of the infected people. Lastly, I don't know if that was the purpose, but certain parts of the soundtracks just ended abruptly, without that "fade out" so it seemed kind of strange...

anyway, it was a great movie! i recommend if you like tension