I'll be honest, I only watched this based on the comments. It is good, maybe just for a one time watch. I wouldn't call it amazing though but that's just my preference. I like the idea of every choice matter. It shows the effects of the choices from one world to the other world. A lot of "What ifs" situations which to me helps the ML understand why he did what he did even though he may have lost his love in his world, to understand if everything he did was worth it and this parallel world showed him that.

It's a slow start for the first 2 episodes but it does get more interesting once this started to reveal the parallel world. If I have to say the highlight of this drama, it would be Shi Yoon's acting. He does a great job portraying a heartbroken police detective in his world and an attitude anger driven guy in the parallel world. The only issue with this is that we didn't get to see much of his parallel self which is unfortunate. It would've been nice to see both of them working together to the end but that didn't happen.

When I read the synopsis, I thought it was going to be Do Won traveling between his world and the parallel world to solve these mysterious murder cases. That's not the case. After showing him in his world for the first few episodes, the rest of the drama was in the parallel world. That was disappointing to me. I would've love to see the interactions of both world's police investigators, working together to solve this, with Do Won jumping between worlds and sharing info or having 1 or 2 of his investigators join in going to the other world, but instead we just had the ML figuring out everything while everyone else (including the FL) was clueless and not as useful as they could've been. Let me also say about the FL. I think she was good character in the original world but then she got killed off and became just a bothersome FL in the parallel world. She was tough but a very aggravating character. I just didn't feel no sympathy for her parallel character compared to her character in the other world.

Is it thrilling? Yes. Every moment I anticipate and want to know what happens next. A lot of scenes are pretty creepy, especially with the creepy background music.

Though there's talk about love between the leads, majority of the drama is not focus on romance so don't expect any sweet or cute moments.

Did I enjoy this drama? Yes, however there are plot holes in this drama that doesn't get answer. The bad guys always gain the upper hand and it seems like the good guys are always a step behind which sucks. I liked how this drama ended (not your typical happy ending) but I feel like there should've been more and yes it did felt rushed as well. Problems to the very end but the way they concluded it was okay for me. Definitely wouldn't rewatch it though. This is a one time deal for me.