Shock Rating
PG
Rated PG, Back to the Future isn't a film that needed much editing before it made its television premiere. The profanity is kept to a minimum (even if the Lord's name was taken in vain on more than one occasion), there's no nudity (although Lorraine comes close a couple of times), and nothing more than slapstick-level violence.
Yeah, this movie was intended to entertain, not to shock. Really, the only thing that was so shocking about the film when it came out in theaters was how freaking awesome it was.