In the opening scene where Peggy Sue is getting dressed and talking with her friend in front of a mirror, it is so obvious that this is not a reflection in the mirror. What the viewing audience sees is the back of two stand in's and a duplicated set as we look into the mirror "reflection". It actually is not a reflection and it is quite obvious as the movements are not at all in sequence. Also, the last scene where Nicholas Cage is talking to Kathleen Turner in her bed in the hospital this same mirror scene is done. What the viewing audience sees is Nick and Kathleen from behind "reflected" in a mirror but once again the movements of the four people in the scene do not move together. You may have to view these scenes a couple times in order to notice.