It gave me a feeling like I am reading something from the world of HP Lovecraft. The black and white tone and scientific approach accentuated that feeling. The story line is intriguing. The performances were superb. It would appear midway the film that you have guessed the story right. However, I suggest you hold on your conclusions till the end. There have been a lot of stories around time traveling. In most of the stories, some protagonist will travel back in time to change one or many things. This film, however, gives a short and simple message. Something that the three-eyed raven says to Bran Stark in Game of Thrones, "The past is written, the ink is dry.."