Anachronisms: When Marty is driving the taxi at night in the early part of the film a car can clearly be seen in front of his. This is supposed to be set in 1988 yet the car in front is a Ford which dates 2006 at least.
Anachronisms: When Marty walks into the bakery to see his girlfriend and child, a 'Scores on the Doors' sign is visible on the door as he opens it - 'Scores on the Doors' didn't come into effect until 2005 while the events in the film are set in and around 1990.
Anachronisms: (At 1:41:44) You can clearly see an poster add for iPhone when they are driving. iPhones were not around at the time the movie is set.