Firstly, I'd like to say that 3/4 stars for the story are dedicated to the first eight episodes. It was so gripping. The storyline was insane, the chemistry between characters wonderful. But, as soon as everything became a "dream", I lost touch of Kang Chul. His character seemed so different (understandably so, he knew and experienced different things), and I had gotten so attached to the first version of him that the new him felt lackluster.
The first half was so fast-paced which made it so hooking, but I think that's also what brought about its downfall. The story wasn't ready to be fleshed out over 16 episodes. The writing got sloppy, confusing, and filled with plot holes. By the end, it became so unbearingly slow, and I was dragging myself to finish it.
However, I did enjoy Jong Suk's acting and the OST by Park Boram.