Waouh thi s drama left me speechless. I rarely give a perfect 10 but this one really deserves it.

Story: the writting is beautiful.
Usually time travel drama are filled with plot hole and unexplained part. Here I couldn't find any . The story is coherent and mind-blowing . There are many twists and they come in a well paced way. This a 13 episodes, intricately and perfectly plotted drama, There relationship between the characteres are well played and help to understand the female lead.
I will just say that the lip reading ability was a slightly exagerated.

Acting : they all pulled off their characters so well , Especially, you could make a distinction between the multiple characters hat were played by the same actors.

OST: i can't remenber when was the last time i've let the credit play to here the music. Overall the OST was good .
I might avoid listening Wu Bai's "Last Dance" for a will because it was overplayed since it also serves as a plot device.
The other song are beautifull.

Rewatch value: the story were the twists and how deftly the story leads you in different directions was the core of the drama. Although that power is lost by rewatching,it will a good occasion to check all the clue that i missed.