When I started this drama, the entire cast except for Yoo In Naa was 'alien' to me, heh. I noticed there was a big hype over Kim Soo Hyun and I've even read an article that said Jeon Ji Hyeon has made her big comback with this role after some 14 years. The premise seemed intriguing, the reviews practically tugged at your sleeves to just go ahead and watch it already, and having done so, here's my little review. For those who love the original Star Trek series, they will notice a similarity between Mister Spock and the main fella, with all of these quite troublesome feelings you get because Do Min Joon has different lifespan from everyone else and you start watching this show knowing how many people he'll lose down the road. Which is very terrifying to think about and might make it hard to watch in later episodes. That aside, don't worry, he is nothing like Mister Spock because he has executed his own character well, and frankly, he made his extraterrestial background very visible throughout the series. On the other side, Chun Song Yi was hilarious. I think she might be the most fun female lead in any series that I've seen so far, because she's not afraid of expressing herself fully in any given scene. As a couple, they complement each other in every sense, their chemistry is completely functional and the comedy relief scenes are up to the task in most parts. Jeon Ji Hyeon and Kim Soo Hyun have done very well in their roles, I think that KSH is growing to be a great actor and I'm looking forward to both their new dramas/movies. From the other cast, Lee Jae Kyung was an incredible character up until last few episodes, I hate how small they made him in the end, he had the skills to pull off an entirely different, more impactful, lasting version of himself. I also liked Oh Sang Jin as he reminded me of classy old detectives and he was very cute while doing so. Music is okay, nothing too memorable but nothing too awful either, the main ost is very heartfelt and nice to listen to, and the overall musical background has been timed well with the scenes. As for the rewatch value, it's definitely a drama I'd watch again after some time, it has all the needed elements for it. However, I'm not a fan of overly angsty plots so this takes quite the score from the rewatching for me. I loved this drama. There was an abundance of romance all around, bittersweet chunks that left the tissues wet, hilarious parts where I would rewind just to see them again. I watched the last few episodes slowly just to prolong the experience, which serves to show how enjoyable it was to watch. However, the score is 8.5 because of the immense angst toll from the second part, it completely faded out everything else. I also disliked how DMJ was tasking everyone with protecting CSY! In last two episodes it made me very irritated how jumpy the others were around her, she's a woman of her own, for cat's sake! And Lee Hui Kyung, you'll never move on? It's been twenty years man, come on! But aside from these two things, I liked the ending. I find that it was the most proper way of saying goodbye to this drama. Recommended.