Now that I have watched the show completely, I really think I should go back and thoroughly revise my review accordingly. This is probably going to be a very controversial one, so prepare yourselves to hate me all you want.

First off, let's start with the good thing (yes as in singular word "thing"! the only good thing!) about the show. I think we can all agree that this show wins the prize of the BEST VILLAIN OF THE CENTURY! In fact, I believe if someone's going to watch this show they're gonna wanna watch it for the sake of the villain's splendid acting skills. The actor does an amazing job of displaying controlled and uncontrolled rage and you will believe him to be a true devil. So when watching his scenes, get ready to have your mind blown away! Pay attention to his mimic and expressions and how smoothly yet drastically they change and you'll know what I'm talking about. Among all the characters in the show, he is the truest to the character and the most believable one as well. Now that I lay the only positive point about the show out there, off to the review:

Story:
The most buggy storyline I could have ever imagined for a show with such a strong concept! I mean, there are exaggerations flying all around the ML. The show tries too hard to depict him as a capable invincible vicious man and pushes it way too far to the point that logic falls apart and at the end of the show, everything seems stupid and out of pure luck instead of due to ML's capabilities. I mean, the scene with the birds helping him out, even if taken from a comedic point of view, has too much of an impact on the outcome to be brushed off and is too absurd to be acceptable. Also, how come every single person who joins forces with ML suddenly becomes the most capable person you could find in the whole country, but anyone on the villain's side seems not to have any brains? Even the villain's lawyer fails to think straight and prepare for a fight, to the point that the villain goes into a warzone with only 4-5 bullets in a gun he just randomly had to grab from his brother's belongings. The funny part is, people are only capable and smart as long as they are still with the ML. As soon as they betray him, they make the most stupid decisions and fail with anything they are planning to do. And WHAT IS UP with the plaza residents ALL being such an out-of-the-ordinarily usefully skilled bunch of people? I mean, every single one of them? Really? Why? Plus, the characters are way too far far away from being consistent (except for the villain and his lawyer), especially the FL! She is very strictly against violence even when she's seeking revenge on his father's death and yet she falls in love and keeps helping this vicious brutal really violent man who is never satisfied with just killing, but prefers to torture people mentally and physically before he kills them off. The FL is a 30-something-year-old lawyer. You would suppose she has more grounded personality traits. But that is so not the case.

Acting:
Well, I already talked about the villain. As for the rest of the main cast, I'm not sure if the actress is to blame or the character description was way too off, but she has the most unreal character among the main cast. I did not enjoy it at all. The ML on the other hand did pretty well, as Song Joong-ki usually does. However, compared to the loud character of the villain, the calm and relaxed character of the ML does not make much of an impression, even if the ML does throw his stunts and overcomes one challenge after another. I've never found myself rooting for the villain in a drama and I personally believe it's important to keep the drama focused on a strongly displayed lead role. It takes so much for a show to make me ignore the lead role and yet, this drama somehow managed to do that.

Music:
I'm probably being harsh on this one since I have a very particular taste in music, but none of the OSTs stood out for me.

Rewatch Value:
Nope! Not a chance I would go through 20 episodes of stupidity again! I wouldn't even recommend watching the show for the first time unless you already know you are up for a huge waste of time with draggy slow motions and scenes of the ML staring at walls and drinking wine while listening to music and you are willing to do so only to witness outstanding acting from the villain. Honestly, this is the only reason I did not drop the show, and do not regret watching it.

Final thoughts:
*****SPOILERS ALERT*****
I can not get over Ok Taecyeon's splendid acting. He is legit crazy and a perfect devil. I honestly didn't know he existed before Vincenzo aired since I'm not really into KPop and somehow I have managed to tiptoe around all his dramas over the past 15 years of me sweeping KDramas. At the same time, I really loved Song Joong-ki ever since Nice Guy aired, and even more so when Descendants of the Sun was released. But MAN! For me, Taecyeon's acting makes Song Joong-ki's role disappear in the background. He really killed it here.
I have to admit now after watching his previous dramas (notice that I loved his acting so much that I looked up his previous projects and watched them, even the ones from 2011) that he has made great progress with his acting skills. I can't wait to see more of him.
*****SPOILERS ALERT*****