To sum up the premise of this show it could be said that it is a lower budget take on the Hotel del Luna concept, and for the viewers of that show there will be some familiar elements. That being said this show is its own thing and it has a markedly different dynamic towards the ending.
I think the leads made a good pair, and I liked that unlike many dramas where the plot gets redundant or silly after the main pair is together, here that only really happens at the very end, making it interesting all the way. The other actors were also pretty good.
The writing is mostly very decent, there are in fact some very well earned twists in the plot, and the thriller elements work quite well. Unfortunately towards the climax there are two scenes which felt very forced and implausible - that is characters doing extermely dumb things on both sides, it is really weird because it is trivial to change these scenes in a way to make total sense without affecting anything else, and I suggest to use your headcabon to do so.
Overall I really liked this show and I think it is fairly decent fantasy thriller with some romance thrown in to the mix.