in the first beginning, i thought the movie was boring and reficulous: how come can two strangers be so close in one day. but afterwards, i realized i was wrong. When you think more about the storyline, the more you would realize according to details. Rain's ending changes constantly according to what happens in 1999. we can find several clues in the movie. the first ending is Rain was alive and watched her first kiss in 1999 through her room's window (we can see a scene where a middle-aged lady watched them behind the window); the second ending is that Rain was dead on the desk because she travelled to 1999 on the graduation day and her heart was broken; and the last ending is jay travel back to the 70s and they had a different love story. hopefully, the movie has a happy ending and also leave some space for our imagination.
i am also impressed by jays piano operation, which is a feast for music lovers. some of jay's striking songs played in the movie is another highlight.
in a nutshell, it is an awesome movie with a combination of carefully cultivated timeline and jay's music talent.