I really liked this concept of this show, but the ending wasn't very satisfying. In the first half of the show, we were introduced to all the characters and given many questions that were left unsolved. This show had so many characters, so I was able to excuse the first 8 episodes for being slow as I expected the pace to start building up after we learned more about the world. I didn't mind all the questions, motives, or the other confusing things that couldn't be explained yet, but my issue was that the explanations would be pretty lackluster. The prime minister's motive was kinda lackluster for me; She climbed all the way up somehow and then wants to be a queen. That's a kinda dumb motive. Then there's Lee Lim who wants to be the king. That motive for me was ok, but then he goes back in time and kills himself? Adding on to that, how did he get all the way back to the present so quickly after he died, but Lee Gon had to take so long? Also don't get how whenever some went through the portal who didn't have the flute could move, because you could only move if you possessed it. Also don't get how time resumes whenever it's convenient later on when time was supposed to stop for long periods of time. Also don't get how some people retained memories and some didn't. I never understood how Tae Eul ended up falling for Lee Gon since that was never explained.

BTW, what did Luna even do with the key card?

pointless reveals/scenes/underutilized stories
the captain detective's meetings, going to visit the kid
lady noh's past
koo's mission/story
lee lim using lee hoon's mom to cause chaos but also wanting to be the king???
Jo yeong and jo seob and their promise
corea vs japan
pregnant woman

the ending was bittersweet for me. in the end, everyone had a happy ending but i wish they had all kept their memories. It doesn't make sense that only 3 of them got yo-yo boy's mercy but not everyone else involved.