Derailment has a very compelling premise and a pretty good twist so I was entertain and engaged throughout the whole series despite some lows for the show as a whole.
1) The actress playing the FL is INCREDIBLE. She will be well known soon and I will watch everything she is in moving forward. She is incredibly talented and a big part of why I stayed engaged with the story the whole time. I recommend watching just for her performance.
2) Speaking of acting I don't know if the actor playing the ML was the best choice. I've seen him in other romances and never had a problem with his performance but I don't think he pulled off the smooth and collected guy-in-charge part of the role. In the moments of warmth, kindness, and caring with our FL he did great and I think his previous experience translated to that part of the role.
3) The main sci-fi and mystery element got a little overshadowed by the FL's day to day in the later part of the show which I think displeased viewers who were mainly there for that. I however, like seeing these parts of the FL's character because it was the first time we get to see her happy with her life. However, it did feel like they rushed back to the main storyline for the last episode.
4) Romance is a part of the story but it's not a major component and there's not much lovey doveyness to the romance so if you want to watch it for the feels I'd pass.
Overall, I liked the show the whole time I watched it; I was never bored and don't regret watching it. Although, I doubt I'd watch it again. So if it seems interesting to you, I'd recommend trying it. It's definitely not a hard pass but it's not something I want everyone I know to watch.