The plot is brief, concise and presents the main points of the story in 6 short episodes. There were no unnecessary plots, it portrayed, the cause, the effect and the final result in the most straightforward manner.
I saw some people say the lack of emotions of the characters was a drawback but I think the characters were just perfect. Given their situation in a post-apocalyptic world, if they start crying and bawling at the deaths surrounding them, then that's when they will go out of character. They weren't inhuman, they were just surviving, and no matter what they needed to go ahead with their lives.

I like this fresh idea for a post-apocalyptic drama and a nice change of scenery. The cast was perfect and yes Kim Woo Bin nailed it!