I've been calling this "The Howl's Moving Castle Princess Fiona Sailor Moon-ification of Jeong Eun Ji".

If you're lucky, this show will trigger a shower essay on the specific kind of "noble idiocy" that denies true character development. But don't hold your breath.

1) the pacing was good. The story moved quickly with lots of action.
2) the production was good. The sets, the acting and the costumes were all good.
3) there were funny bits with a lot of visual gags and role reversals
4) there were a lot of twists and turns in the plot
5) the plot was a mess and the characters were a mess. So, your OTP mileage will vary.

If you have better things to do, this is a hard skip. But, if you want to be entertained for 16 hours, it is a way to pass the time.

I liked the show most of the way., more than a lot of beanies, it seems. There was a lot of funny scenes and misunderstandings that made for surprising ways of acting. And several roles were just very well filled.
I liked both versions of the FL, though I think they could have done even more to integrate them to that one person they were. The older FL was better at being young than the opposite, but still ... it was okay.
I deeply hated the noble idiocy, especially when it was not about life and death at all, but just an inconvenience the FL wouldn't allow the ML to have, even if begged for it. And the time skip was extra meaningless.
Like in many fantasy kdramas, I don't think the premise was explored enough, or given enough reason. There was the "escaping from being found out", and that was really well done, with climbing on the outside of a house one time a favorite. But how about the respect ajummah would earn? Could it have been fun to see her treated with the respect of a grownup? That could have been part of her realisation that the way she felt dumb was not solely conditioned by how smart she wasn't, but much more on how much others respected her.
This is something we hear from transgender persons often: That suddenly, their opinion is respected/not respected, dependant on their gender presentation. THat experience could have made sense also as something she needed for some time for her to return to her actual age and carry that respect for who she was and what she could do with her in her heart.
I was well entertained most of the way through and looked forward to the next episode. I would have liked if the story could have made it through without murder and gore, I think. Or if the magic and the murder could have a closer connection, so that one thing necessitated the other.

Lee Jung-eun was on fire and there were some good parts too. Perhaps they promised us a light-hearted romcom, but since the romance was postponed a lot, some people, including me, were frustrated.

https://kdramadiary.com/kdrama-review/miss-night-and-day-jtbc