If you’re one of those who sit at home on a Saturday night watching classic movies on TBS (and let’s be honest, all the cool kids do), chances are you’ve watched Back to the Future at least a dozen times. It’s one of the most watchable and quotable movies of ours or any generation. If you haven’t seen it, then crawl out from the dark hole in which you’ve seeded yourself and watch it because it is, indeed, timeless (no pun intended).

As most of us already know, or ought to, Back to the Future is about a teenager, Marty McFly (Michael J. Fox) traveling back to the past in a time machine built out of a DeLorean automobile. In doing so, he accidentally alters the original course of time and inadvertently sabotages the moment in which his parents (Lea Thompson and Crispin Glover) are supposed to meet, fall in love, get married, and have children - one of which is, obviously, Marty himself.

With the help of eccentric Doc Brown (the ever-hilarious Christopher Lloyd), and the knowledge he has of the events that led to his parents’ matrimony, Marty must now find a way to again get them together before time runs out and he is not only stuck in 1955 but erased from existence altogether. Of course, this is no easy task. With time literally against him, as well as brutish numbskull villain, Biff Tannen (Tom Wilson) also vying for Marty’s mother’s affections, Marty has to overcome the numerous obstacles placed before him and set everything right again.

What’s great about screenwriter Bob Gale and co-writer/director Robert Zemeckis’ film is that it takes the high concept movie formula (which always presents the danger of manufacturing a forgettable product) and turns it into one of the best movies of all time. There are certain proven structures (such as Joseph Campbell’s Hero’s Journey) to which screenwriters try to adhere in order to make a perfect movie. Almost no other movie I’ve seen has been structured so perfectly as Back to the Future. In a traditional three-act structure there are actually four points that need to be hit.  Normally around the 17 minute point something disrupts the “natural world” for our hero.  In this case it would be the introduction of the time machine (at the 18 minute mark precisely).  The end of act one, generally around the 30 minute point, is when the hero takes off on his journey and the adventure begins.  Marty (at 31 minutes) is blasted into the past and, thus, his adventure has begun.  The midpoint, at around minute 60, is when the hero makes a change by going from a passive character into an active one.  Throughout the first part of the film Marty has relied on others to help him figure things out and get back to 1985, but at the midpoint of the movie (at 62 minutes) he actively dresses up as the not yet invented “Darth Vader” from the planet Vulcan to convince his awe-struck, sci-fi nerd future father to ask his future mother to the dance.  Finally, the end of act two or the low point (usually at around the 90 minute mark) is exactly what it sounds like – the lowest, most dire moment in the film, where the viewer asks, “will our hero live or die?”  The low point of this film doesn’t fail us: at around minute 85, Marty starts literally to disappear into thin air on stage at his school dance, as his time is running out – until everything he’s set in motion with his parents finally begins to turn things around toward his eventual success.

The beauty of the movie isn’t just in its perfect structure or its many complications, although there are a ton of them, such as Biff ruining Marty’s plan to have his father save the day, the DeLorean not starting when it needs to get to the lightning, Marty’s teenaged mother falling in love with his own teenaged self and thereby making himself an obstacle to his future father’s chances, or the extension cord up the clock tower getting disconnected by a fallen tree branch. Even after seeing the movie half a million times, just try watching the last fifteen minutes without biting your nails and having to reassure yourself that everything will turn out okay.

Part of the beauty of the writing is in its depiction of its characters, and in how well their dialog works both to define them and underline the subtext. Every single line uttered and every single action taken in the movie is a set up for a pay-off later on in the film. Listen to the dialog that every character speaks in the first half of the movie and you’ll find that it is a set up for some rewarding repetition with a twist later on. For example, after Marty’s band is rejected for the high school’s “Battle of the Bands” competition (with a wonderful and ironic cameo by 80s rock star Huey Lewis), his girlfriend tells him that he needs to submit his demo tape to a record company, to which Marty responds by saying, “What if I take the tape in and they don’t like it, what if they say I’m no good, what if they say ‘get out of here kid, you got no future’? I just don’t think I could take that kind of rejection.” These lines have so much subtext to them: On the surface, Marty is worried that he’s never going to make it as a rock star, but underneath it’s his way of stating that he’s concerned he’s never to going exist – the platform upon which the entire conflict of the movie is based.  Similarly, when the high school principal corners Marty, calls him a slacker and says, “No McFly ever amounted to anything in the history of Hill Valley.”  Marty responds with, “Yeah… well history’s gonna change.”  Again, the subtext behind these lines isn’t just about Marty and his quest to make a name for himself and not following his father’s footsteps, but about the fact that he is literally going to change the course of history for both himself and his parents.

Writers Zemeckis and Gale do a brilliant job of using lines like these, that appear to be just throw-away bits of exposition, and adding layers upon layers of underlying meaning and importance to them. They even found a brilliant way of personifying the antagonist of time itself. Time is what Marty’s up against.  The opening scene begins with more than a dozen ticking clocks.  Marty is constantly late to school.  He almost misses meeting up with Doc Brown at 1:15 in the morning because he wasn’t awoken by his alarm clock. Most significantly, the only way to get home is for lightning to strike – what? A clock tower! It’s a visual representation that recurs again and again on screen, and that has been present in Marty’s line of sight for his entire life. We love this movie not because we realize all of these set ups and payoffs, but because they’re done in such a way that it not only gives vital information to the viewer, but in a way that they’re entertaining as well.

This isn’t to take away credit from the actors. Back to the Future wouldn’t have been the success it is today without Michael J. Fox, because during the first five weeks of production, Marty McFly was first portrayed by actor Eric Stoltz. Zemeckis ended up re-shooting these five weeks because Stoltz’s comedic abilities were lacking and the movie felt flat. Fox not only made it funnier, but the movie became the sound vehicle Zemeckis and Gale wanted to drive.