BACK TO THE FUTURE is a classic. I can't say as much for the second installment in the trilogy, BACK TO THE FUTURE PART 2, but it's a pretty darn good sequel.
The tone in this one is darker than in the first, but the content level is pretty much the same. Langauge is, like the other one, constant, and there's a moderate amount of sex too. The married villian is shown in a bathtub with two assumably naked women (nothing but shoudlers are seen, as there are bubbles in the bath). The main characters mother, unhappily married to the villian, gestures at her breasts and says "You were the one who wanted me to get these THINGS!" Violence is mild, with a few kicks and punches.
This film is worth watching if you're determined to see the entire trilogy or are a big fan of the original. The 1955 sequences from the first one, viewed at a new angle, blow your mind. The biginning 2015 sequence is a bit cheesy, but a brilliant cliffhanger patches it all up well. Michael J. Fox and Christopher Lloyd were made to be in this movie together, and are brilliant onscreen.