Sorry for the dragged review but I just had to.
I was excited to watch it but sadly it did not meet my expectations. I liked the side characters which includes: the royal guard who was Woo DO Hwan and his counterpart Eun sop because honestly not just were the characters very interesting but also his acting and his duality was INCREDIBLE which made me love him even more, Shin Jae was also a very interesting character and the actor was just amazing with what he was given, the prime minister's character could've been so much better and stronger than what they made her, and Na-ri and her counterpart were also my fav characters but given their limited screen time I was disappointed.

I hated how the whole "love" part was over exaggerated and forced like the whole drama would have been perfect without it. But seeing as they intended to include it, they could have added more of a reason for them to fall in love not just a forced type of love like they didn't seem to have anything in common but I would like to admit that Lee Min Ho's scenes where [spoiler] saves her from his uncle and the scene where he traveled for yours for her [/spoiler] were romantic but didn't work with the forced relationship.

Jung Tae Eul's character wasn't very interesting or entertaining and nor was Lee Min Ho' overly scientific and know it all character.

And do not get me started on the ending which was stupid to say the least.

Also, some things were left unanswered and were confusing:
[spoiler]
- Why was lady Noh brought from the other universe.
- What was the yo-yo kids story and how is he from both universe'?
- How is Lee Lim young even though time passed? Is it because he travels the universe's and if so is it happening to The King as well?
- When Lee Gon changed the past how exactly did it effect the future and was the change in the past supposed to happen?
- When Lee Gon went back to the past during the row competition why did he leave the stables access card in the jacket for Luna?
and many more confusing things.

[/spoiler]