Has some implausibilities, but is nonetheless amusing.

Rating: 7/10 (28 October 2016)

This is total conjecture, but I don't think that the story of this movie would hold up with modern audiences. Nowadays, we all find plot holes and reasons why certain parts of a story aren't true to life or human nature. Put Back to the Future under that kind of scrutiny, and I don't think it passes the test. I guess people just didn't watch movies that way back in the '80's. They didn't care that all of Marty's dreams magically came true at the end in Disney fashion; they just wanted to have a good laugh and have another thing to quote. This may be a very shallow view of the '80's, but the fact remains that audience expectations have changed drastically in the past 30 years. Even if you look at how the time travel element is handled in this and in Bill and Ted's Excellent Adventure, compared to how it's used in Interstellar and X-Men: Days of Future Past, there are major differences.
Regardless, it's easy to see why this became a classic and resonated with it's viewers. It has a fairly interesting plot, but is very easy to follow. It also has a lot of fun lines and exciting scenes. The use of setups and payoffs and callback devices is done very well. It may be a bit on the nose in displaying the similarities and differences from '85 to '55, but this fits with its identity as a comedy and saves the audience lots of confusion. The exposition in the beginning is also vital to nearly all of the ironic and humorous situations that payoff in the 1955 setting. However, all of the events discussed in 1985 all conveniently happened during the same week in 1955, which is hardly plausible. That aside, it is impressive that the writers were able to squeeze that much information into the first twenty minutes in such a way that it would be easy to recall.
But what we care about most when watching a movie like this is whether it makes us laugh. Any comedy can be mostly excused for its plot holes if it succeeds in amusing the audience, and I would say that Back to the Future succeeds for the most part. It may not be gut-wrenchingly funny, but it is nonetheless amusing throughout. If nothing else, it is interesting to see how Marty interferes with his past and how he discovers just how unbelievably sad his parents' relationship is.
This makes for a pretty good all-ages comedy. It's easy for even the youngest of viewers to understand. There's a bit of language and sexual tension, but all of the awkward scenes between Marty and his younger parents are done in such a way that the awkwardness is palpable without being raunchy or gross. There aren't any plot holes, per se, but there are a number of clichÃ©d moments at the end and a few implausibilities in how the time travel works. Obviously, Marty's world wouldn't necessarily be better after his trip, and it's still quite possible that he wouldn't have been born or turned out the same way. But it keeps things simple and adds a nice little cherry on top. If you haven't seen this, just be aware that it is loved as a classic comedy and did not achieve its status by great execution. Certainly it is superior in many ways to other '80's comedies, but it might seem overrated to a modern viewer. Overall Rating: 8.2/10.