When I started this drama i expected something that goes in the star treck or star wars direction. Of course i knew it was a drama based on romance and that it would never be anything like that, but when i heard the word "alien" i expected something scifi-like. And I'm glad i was wrong, because i hate those things. Thats why i first didn't know if i should watch it and i'm so happy that i did. This drama is the best i've ever watched since boys over flowers.. at least for me. I cried so much at the end, not because of it's ending but rather since it was over. I'm a huge fan of Kim Soo Hyun since dream high, but compared to this drama .. whoo.. he became soo hot. I've gotta admit that the actress was new to me (i've started watching k-dramas in 2012 so don't blame me please~). But i loved the chemistry between those two. At first i kinda disliked her character, because she was so arrogant and full of herself, and dumb. But when the story continued you've got to see her soft side and that she was a kind person, but still she was hilarious from the beginning til the end. I laughed so hard, i almost cried. And the male lead was kinda hard for me too, because i don't really like those characters that act so mean in the beginning and so play so hard to get, even though he has a pretty good reason. The minor characters where adorable too. I personally loved Cheon Song Yi's little brother. He was so cute and the bromance with Do Min Joon was great. Even the evil guy was great. I really really hated him to death, which proves how great the actor was. The soundtrack was awesome. I loved the song "My Destiny by Lyn", but it was kinda annoying after some time. And because i'm (now) a huge fan of Hyorin from Sistar, i loved the track "Hello Goodbye". Thats the two songs that were stuck in my head, even til now. I would definitely say it is a drama that is worth watching, even if you don't like alien stuff and such. But for rewatching i would say you should wait a while before restart watching. I waited like half a year and i coudn't remember a little things so i rewatched it.