I love the originality of the idea! For this drama, it actually made sense why the world is not traditionally historical but fantasy historical because FL made it up to begin with. It was so fun to watch ML and FL fall in love with each other and the acting - especially of FL - was amazing! I needed this lighthearted and funny drama.
But I can understand why some people might not like it. FL was childish quite a few times (especially in the beginning). But I loved her character development to become smarter and more serious. What bothers me a bit is that although it was really fun to watch, it was still a bit too long. But I think this is a general cdrama issue.