I am glad for people's positive reviews which made me decide to give this drama a try, and having did I understand the reason such a low budget drama is gaining so much popularity.
I loved the whole story including the time travel element, and even though there were minor small gripes that I had with the mechanics of the time slips etc, it stil never ruined anything for me. The backstory to how the miraculous time travel capabilites first come about are never explicitly stated but the viewer is shown hints as to who to thank for it all, which made everything all the more heartfelt and emotional in the end.
The best aspect by far and one that I believe accounts for 100% of the popularity this show is garnering is without a question, the romance. with an endearing love story and marvelous electriflying chemistry, watching and re-wtching their scenes together and the behind-the-scenes, it shows very evidently how the two lead actors had built in real life such great rapport and a strong relationship based on trust and respect, and hopefully even more than that ♡
The acting was very strong by the whole cast especially our OTP who did a marvelous job conveying all ranges of emotions and levels of emotional maturity.
The comedy parts were pretty well done with a lot of laugh-out-loud cringe inducing hilarious parts, thanks in particular to a marvelous set of side characters including the ML's dad, the FL's mom and older brother, the FL's old time crush Tae-Sung and In Hyuk our ML's best friend.
the OST was lovely and despite the fact that first time watching not many tracks managed to particurarly stick with me, later after rewatching parts of it I found myself humming a few tunes even sonagi <3

If there are any negative comments worth mentioning, it would mostly concern the villain and the whole serial murderer arc. I know that the story needed a plot device to push it forward and into the danger and angst zone, but our bad guy was just that, too bad and psycho down to the core, but the story never bothered to show us any sort of background story to flesh him out or show us the motives behind anything he did or his seeminly deeply rooted grudge against Sol & Sun-jae, so he ends up as a 2D caricature of a bad guy, whenever he pops up on screen I am rolling my eyes rather than being on the edge of my seat.
And also there is just too many times that the writer is allowed to use the exact same plot device before it becomes too repitive it essentially is no longer surving its purpose but rather it's cheapening the worth of the whole story. I mean to sum up all troubles our lead couple could ever and will ever face together all in the mere existence of one villain, was too much for me at some points. I understand that if the story was that she was going back in time to save her love after getting hit by random traffic or some other type of accident, it might have had its uncertainties and would have felt like defying fate, and I guess the writers were playing at the concept of destiny involving both good and bad bonds, so people who were meant to cross paths are destined to do for better or for worse, but I couldn't help feeling like I would have appreciated it more if there was more time given to delve deeper into our bad guy's story and psyche so he would not feel like a wack-a-mole puppet popping put every couple of episodes.

Overall despite any minor shortcomings this drama might have, still a marvelous romance, lovable characters and spectacular cast manage to turn it into as perfect a drama as any romcom could ever dream of being.
So even though the objective part of me couldn’t help criticizing certain indiscrepancies about the time slip element which can not be said to be the most original out there to begin with (what with all the other time slip dramas that come out each season), or the annoying villain, Still this drama has managed to steal a spot in my all time favorites thanks to nothing but the main lead's chemistry and swoon-inducing romance. Proof is the fact I immediately went ahead and re-watched all their scenes together. I recommend highly to any Kdrama fan out there.