First, the ML and FL and their chemistry were excellent. The rest of the cast did a good job with what they were given. But the story was uneven, funny moments felt super forced, and the dialogue was often stilted.

I love a good fantasy / sci-fi romance, and in a fantasy/fictional setting, I'm open to the idea of a robot / human love story, otherwise I wouldn't have watched this kdrama. But this drama never fully committed to the idea, and thus it suffered. I wonder if it was the director or the script writer who had a problem with the concept. It felt like the story kept apologizing for the idea which undercut the concept and left the end ultimately unsatisfying.
I want to compare this one to 'I am not a robot,' but don't want to give any spoilers. Basically, the difference between the two is that this one seemed embarrassed by its own premise and that one fully committed to the idea.