If you're looking for a simple story, move over and watch other dramas out there because this is not meant for you.
The story has a certain charisma of bringing sci-fi to a lighter romance novel-ish type of feels. Sure first few episodes will make your mind think like "WTF am I watching??" but as the episodes progress you get the satiafaction of finding out the reason behind everything that happend in the previous episode.
The director was so clever in putting lots of small hints and details that you will definitely see once you rewatch the episodes because they will make you rewatch to have that "oh did i miss that? let me see that again" moment.
You definitely need to level up your perspective in this series. It feels like Inception, Oldboy, and Fringe put into one pot, sprinkled with Korean Royalty and boiled in one sweet and spicy revenge water.
Overall, it was a good watch. Probably best not to binge watch at first then rewatch after you finished to check back on the cool details you might have missed.