It's nice and it's not. The idea is there but the execution sucks. It's a good teenage drama, but damn it is hard to watch after episode 6. There is no growing/character development for the FL. It's like watching two Im Sol with split personalities, no maturity on the 30 yr old Im Sol. It's like watching both 18 year old Im Sol with out any contrast to their character. The plot in the beginning was on the right path, everyone's lives are getting better. But the 30 year old immature Im Sol kept screwing things up over an over again for everyone. As if her brain never developed at 25. At first she's Ok, have a potential to be likeable. Like I thought while saving sung jae, she will improve lives of everyone else. That was the intial plot (Ep 1 to 6) But plot twist, NOT. (Ep 14 to 16). They kept adding unecessary filler stories that doesnt add much essence to the story as a whole. It's nice but it was stretched too much (Ep 7 to 13). The killer doesnt even have a direct motive. It's like a glitch, the dude is like a running virus. It just kept following and killing them for all the timelines.
Timeline 1 - Sungjae died, she returned.
Timeline 2 - Sungjae still dead, she returned.
Timeline 3 - Returned to present. She could walk and got her dream Job. Sungjae was attacked, Lost a lot of blood and unconcious. Returned with in the same night to rewrite the past even though Sungjae was only in the hospital for that night. No updates yet, she returned. Tae Sung improved, Eclipse now struggling because they didnt get to be discover (im sol stopping sungjae to be discovered). Im Sol and Sungjae in college. Sungjae and Taesung relationship growth. Sungjae dad and Sol mom relationship growth. Im Sol made herself the bait by not leaving with sungjae and others. Lied to her mom that she's with sungjae. Sungjae Died. Returned in time again because sungjae died (because of her, again!)
Timeline 4 - Everything went to shambles. Everything stopped making sense! (EP14 TO 16)