Apparently this is a remake of a Japanese series and movie by the title of Paper Moon. As such, my one problem with the drama, (the ending), becomes a bit moot. I like things tidied up a bit better, but it wasn't a terrible ending, and many things did get some closure.
I'm a big fan of Kim Seo Hyung, and she did not disappoint here. She has always exuded such presence that it hurt my soul to see her portrayal of a very intelligent and capable career woman stripped of all self-esteem by her self-absorbed husband. Her exceedingly lonely existence was its own tragedy and lent itself as the driving ingredient for the events that followed.
There's certainly room for debate about some of the character's choices, but there's also a great deal of deserved empathy for the underlying emotions and motivations for those choices. It's all quite conversation-worthy.
I found the so-called May-December romance to be quite believable in that it wasn't a rush of sheer lust. Just a quiet longing for attention and affection during a crisis in each of their lives, that also included attraction and intimacy. They filled each other's needs at that time - which often gets mistaken for real love. Those kinds of relationships rarely last, even without an age gap. Once the crisis changes or is resolved for one, the foundation inevitably cracks. And for this particular culture, having relatively realistic intimacy scenes, and showing that a man his age not only can, but actually often does, find an older woman attractive in that way, was extremely refreshing.
I very much enjoyed the noir style the director chose, the soundtrack was subtle - meaning nothing caught my ear as either memorable per se, nor distracting. I even liked the unobtrusive intro and let it just play each episode.
Now that I understand this to be a remake, I'm not expecting a second season - though I would be over the "pale moon" if they got creative license to do so. If you aren't a fan of subtle noir-style, slow-burn, have some kind of problem with older woman/younger man, or will find yourself very upset with adultery from a woman's side, no matter how many men get away with it - this won't be for you. If you can handle those things and want to watch several great performances, (including the elders of this drama - who get a chef's kiss), then I definitely recommend.