I think this drama deserves to get a 2-digit rating and is in first place in the OTT rankings. Here's why:

The actors' acting is extraordinary. Honestly, this is the first time I've seen Chun Woo Hee and Claudia Kim's acting, but their acting is really wow. Moreover, Chun Woo Hee... there is a reason why she is a Chungmoro. The quality of her acting is above the average Korean actress I have ever seen. And Claudia Kim, I know she's played in Fantastic Beasts, but I've never actually seen her act. But when I look at it, wow... so far, of the many Korean dramas that have the theme of body transformation, the depiction of people with large bodies is the most similar to that depicted by Claudia Kim. And I was amazed by the stylist who paid attention to the details of the transformation from the neck to the fingers.

As for Park So Yi, I've been attracted to her acting since watching See You In My 19th Life. And her acting is really that good and cool... if she consistently stays in good projects like this, maybe she can follow in Kim Hyang Gi's footsteps.

Lastly, Jang Ki Young's acting. One word, WAH. I watched quite a lot of Jang Ki Young's dramas, from Come and Hug Me, until the last time I saw him briefly in the drama Now, We Are Breaking Up. His acting is really good and satisfying in this drama. The best compared to his previous dramas. Maybe it's also because, in the end, he didn't get the role of a cool guy or a little talker, here he stepped out of the character he usually plays, really friendly hahaha.
And what amazed me the most, in episode 12, was his acting was crying, wow... I didn't know he could act that well. Until the veins on his face pop out too. This time Jang Ki Young can finally shine in his drama. If I remember correctly, Jang Ki Young has often been a male lead, but usually, the female lead or other actors are highlighted. But now he has finally succeeded in really giving off his aura in this drama.

This drama can highlight all the existing characters and doesn't make us feel like we're wasting time when scenes other than the main character appear. Even the excited Loveline between I Na and Joon Woo is one of the most eagerly awaited scenes in this drama. Da Hae's family all have strong characters and are really wow. All the actors here managed to attract the audience's attention even though they didn't have much screen time.

What makes this drama deserve more popularity than it is now is the plot. This drama only has 12 episodes, and it was the right decision to make this drama only 12 episodes. Just like when I reviewed Revenant, this drama also has a neat plot and very few plot holes. Each episode is reviewed interestingly and even though there are a lot of back-and-forth scenes, it's not confusing at all because it's made that clear.

I'm a fan of stories on the topic of parallel worlds. If you research it more, it's not just superpowers or ordinary time travel, but it also has parallel worlds. Like Doraemon who came to Nobita so that he could be successful like in the future where Doraemon was there and it came true, this drama also makes Gwiju in the present go back to the past so that the future where Da Hae is there comes true. And that wowed me. Moreover, the ending of this drama is unpredictable. The ending is not forced but makes good use of ideas and genre.

The production quality, the filters they use, and the soundtrack they use make us feel like we are in the drama when we watch it. Our focus is really on this drama. I'm one of those people who is often skeptical about Korean dramas that have the fantasy genre because so far the only Korean drama in the fantasy genre that has a satisfying ending for me is Moving. But it seems like this drama is the second Korean fantasy drama I am very satisfied with the ending.