This is a drama with a amazing characters and a well paced plot.
At first, I was a little apprehensive about the tone and the direction it was going in: the relationship seemed a little too perfect and superficial, Cha Ji Won and her police team weren't very convincing, and well I was really scared that it would have a sad ending (I hate sad endings). Fortunately with the power of Lee JoonGi I soldiered on and actually as soon as I started episode 3 I was hooked.

I loved the pacing of the reveal that Hyun Soo wasn't actually a bad guy. It was gradual enough that it kept you hooked and I think it was really effective that there wasn't necessarily one big point where the reveal happened. LJG's acting was amazing as well. I loved how he searched Ji Won's face and studied it to make sure of the emotions that she was feeling and little details like that. His delivery of Hyun Soo was exceptional.

At first I also wasn't very convinced of Moon ChaeWon's acting. It just felt like she was to bright, too naïve, and there didn't seem to be much depth to her acting. It was only after she found out about Hyun Soo's identity and didn't tell him that I was convinced. In fact she went on to deliver really powerful acting moments: I got goose bumps when she found him near the swimming pool and several other scenes.

I also really enjoyed the other characters too. I felt here was ta real sense of community within the police team. The writer really did a great job of making sure that each character had individuality and wasn't there simply as a plot device.

Kim Ji Hoon (phewwwww). They should have picked someone ugly to play his character because I spent way too long finding a psychopath attractive. Objectively, he also did an amazing job of portraying his character. I saw on his IG that he had several references for his portrayal and I could really tell that he put a lot of effort into portraying Baek Hee Sung correctly. Fully convincing!

There were slight issues I had throughout the drama though. First of all, it didn't feel like to me that Hyun Soo would be someone who sobbed, and constantly after a point too. I also felt some scenes were just so cheesy.
I almost wasn't convinced by the amnesia trope BUT I think it was important to see that even Hyun Soo wouldn't trust that he was being sincere to someone and it felt like they were able to reset their relationship so that they could start from a place of honesty and love. However, I'm sure they could have come up with a more convincing and organic was to show this.

Also think they sort of brushed his hallucinations under the rug when in real life such things are serious. To be honest he should be seeing a therapist bc of PTSD but alas, kdramas.

Overall, it was a great, compelling drama. Super recommend!