Well... I don't even know where to start...
First of all I am pretty late with this review given the fact when this drama got released whoops, but I don't really care since I need to get this off my chest. Anyone who is interested can read it.
This KDrama was my first medical drama hooray and a very good one I have to say! The medical stuff definitely won't disappoint you in this drama! It was good, everything was so well explained and I had hope with every surgery, feared about the patient's life and of course was sad when something unexpected happened. SO if you love medical dramas this is a must and if you haven't watched any other medical drama before -just like me - it's actually also a must watch because wow. (side note: there was way more blood then I thought there would be though)
The main story was amazing. Just wow. My favorite episodes: 1&2! I kept watching this drama and always had to think about the first episodes. That's when the story started that's when you thought: Wow, how can they even make this end well? I can't state if they did end it well even though I've just watched the last episode I'm really unsure what to think about it. I read many reviews saying this drama had a good start but failed in the middle and I have to say I agree. The first episodes were just wow. And as the story continues I was curious all the time because holy shit there were so many plot twists. That's what made this drama extremely good but sadly... some of those went to the wrong direction and the last episode for example was nothing like the first. It's a sad turn indeed but in my opinion not reason enough not to watch this drama.
As the storyline continues we get to know the characters better or not better? With every decision that was made by the characters I began questioning if I judged them right in the first place. And also, I don't know if I'm just pretty stupid but sometimes it was hard to tell who were the 'good' guys because like I said the characters actions always ended up differently and they had such a depth which was amazing. I'm only talking about the 4 main actors now but actually every single character lived through such a development it's amazing. Just for the character depth I am going to say: watch this drama.
Actually I feel like I am praising this drama WAY too much but here's the point: The cast did such a freaking good job. No wonder there was such a depth. I'm amazed cause sometimes I just couldn't understand why any person would act the way they did and it made me furious but happy at the same time. How was it even possible to act such deep characters? I don't know, but it happened.
Next point, the OSTs. Well damn the situations were already critical enough no need for background music but obviously it did a very good job with making me even more nervous or even more sad which I thought wasn't possible anymore.
Now my negative points: even though the start was very good and the plot twists were exciting too... it got unrealistic towards the end. Very unrealistic. This made me so sad because I enjoyed how it started but the end was nothing like the start.
And let me say something to the romance freaks as well: first of all I AM ONE myself that's why I think I can kinda judge this aspect. It was... twisting. Honestly you would know the main pairings in the beginning... or not? Maybe he isn't going to end up with his first love? No way, of course he will, that's what all kdramas do... wait he really isn't going to end up with her but with the other girl, isn't he? Those were my questions through the whole show and to be very honest until the last episode I had hope for my pairing but sadly I kind of was the second female lead. I obviously won't tell you with whom I hoped 'Doctor Stranger' will end up but it was really interesting to watch how the tables were turned over and over again.

All in all: I'd really recommend this drama IF you love medical and romance but be aware this won't end up as you wish. I think I can speak for pretty many people that the ending was just disappointing. But all other aspects were reason enough to keep going and my biggest motivation to watch this drama was 1. the patients and 2. I wanted to know who the main pairings were because damn I lost some hair because of the romance in the drama. The story started so good and alone the start is reason enough to watch this drama. That's just my opinion though.