Let me be honest. At first, I didn't plan to watch this k-drama, but I did because of Ahn Hyo-seop (I know you are not judging me for that, hahaha), and it was so worth it!
I agree with everyone who said that Jeon Yeo-been's (f lead) performance was outstanding. In that confusing and sometimes shocking time loop, I thought there were different actresses. She managed to play them all too well (like different ages, different people and still played by one person, bravo!)
The main plot as I said earlier was very confusing, yet in a very good way. A few times, I thought that I could predict something, and then everything was changing so quickly that my brain needed to use all of its resources to adapt to the new turns. On Ep.11, it all became overwhelming, and I started to look forward to seeing the final. I'm glad it's 12 episodes and not 16 or more.
While watching the drama, I had thoughts that if I wanted, I could find a lot of gaps or I would have a whole bunch of questions to writers, but I decided to enjoy the series, as sorry, but this is much better and rare than "King the land" or whatever.
Overall I did enjoy watching it. I think you will not regret watching it either.