Other mistake: When Marty returns to 1985 from 1885 the time machine is destroyed by a train. What is strange is that not only does the train not stop (which is mandatory in the event of an accident) but there is also no reaction from people nearby, such as those in the vehicles waiting to cross the track at the level crossing. Later, when Marty returns to the site with Jennifer, there is still no sign of police officers or other officials.
Other mistake: When the movie ends and Doc says, "It means your future hasn't been written yet," watch his son Verne behind. He looks towards the camera and seems unhappy, makes a beckoning gesture (presumably at the crew), and points at his crotch. Seemingly, the kid was having a hard time trying not to pee on himself. (01:50:39)
Other mistake: When Clara is waiting for the train to stop at the train station and the train has steam coming from in front of the wheels, as it passes by the camera it jolts the camera. (01:20:20)
Other mistake: After Mad Dog tries to kill Marty at the bar, a man says "you better run, squirrel." Marty is crouched, 4 meters away from the counter, but in half a second he has managed to stand up, run to the counter, jump on it and run towards Buford.
Answer: Someone would go into his barn and do what? See a sign that says time machine and believe it and then use it? Seems highly unlikely.
lionhead