During the scene that convinced audiences, studios and filmmakers of the future cinema had changed forever, I was lost in another theatre. When the last few previews were playing, my cousin Lynda (then 12) and I (then six) had gone out into the lobby of the Hoyts cinema complex in George Street Sydney in late May 1977 to buy popcorn, and we'd gone back into the wrong cinema to try and find everyone else.

How we realised and found our way back to the right cinema I can't remember, but the rebel blockade runner had been captured and boarded, Leia taken prisoner and bought before Vader, and Threepio and Artoo blasted off in the escape pod bound for the wastes of Tatooine.

That's my Star Wars story. Every fan, magazine, actor, executive and casual pop culture watcher has theirs. To at least two generations alive today, the film isn't just the one that made the strongest impression on them or the one that changed the movies. To many of us, Star Wars simply is the movies. Are little kids in primary school running around playing Watchmen right now, six months after the fact as I write these words?

The reason we all have our story is because we feel it's a part of us, and us it. But it wasn't always that way. Today, a US summer tentpole movie doesn't deserve such a moniker unless it's previewed extensively at Comic Con. In 1977 the influential convention was just about comic books. Movies were about the nihilistic mores of an American political landscape reeling from Nixon, Vietnam and social upheaval.

Fun had come back to American popular culture to some extent with disco surging up the charts, but it had certainly avoided cinemas. Heroes were hard-drinking borderline thugs like Popeye Doyle, who'd shoot a guy in the back as soon as arrest him. Enemies where shadowy elements of the expanding military-industrial complex that lied to us and hunted us down. There was little clear good or evil, just a pendulum swinging through a murky moral haze as we wondered if there was any black and white left in the world.

A semi-successful filmmaker at the time thanks to American Graffiti, Lucas remembered a far more innocent time and with nobody in Hollywood in his corner but Fox exec Alan Ladd Jr, he made Star Wars by the proverbial seat of his pants to realise that old-time mood of the guys in the black hats and white hats.

With barely the budget, experience, trust of his union-dominated English crew or a cohesive result from his nascent special effects business (ILM), Luacs probably didn't have the emotional state of mind to wonder how he and Fox would sell it.

Something the studio left completely out of the deal was a decent marketing budget, and Lucas ending up with the merchandising rights that made him the Charles Foster Kane of movie licensing is only half the story. He didn't think they were worth any more than Fox did, but with nothing else to work with he made his own posters and T shirts, figuring Star Wars' fanbase would consist of kids at Comic Con who read comic books.

Whether the word of mouth of comic book nerds drove Star Wars to the heady heights it's enjoyed since can't really be accounted for, but if you don't know what happened next you must have spent the last 30 years living in a galaxy far, far away.

The script changes Lucas went through before settling on the three central characters (apparently based on Kurosawa's The Hidden Fortress) are also famous, but he distilled every heroes journey from Heracles to Joseph Campbell to come up with his simple plot about a bored kid leaving home to find adventure fighting a war against the dictatorial government that rules his galaxy.

Keep in mind this was long before anyone knew of the soap opera family entanglements that would ensue in the later films (unless you slept under Lucas' pillow, where it's rumoured he hid the treatment and script for The Empire Strikes Back). The notion of a kid who wanted to go off and fight space battles and save beautiful princesses that spoke to every child in every corner of the world seems somehow... purer.

Despite his influence and that of his most famous film, Lucas was never even close to being a good screenwriter. What he did differently was in the design and visuals. Starting with the Ralph McQuarrie pictures he used to help pitch the movie to the Fox board, Lucas is one of the movies' best conceptualisers. If he'd built the world and outsourced writing to others, like he did the direction of the next two films, Star Wars might have been more than just the movie that changed Hollywood, it might have been a perfect movie.

In everything from the iconic character designs like Vader and Threepio to the sets, weapons, vehicles and props, Lucas rebooted the movie industry at a stroke simply because of the world in which he placed his story. A lot's been written about the notion of a 'used' future, where instead of pristine surroundings it looked like the world of Star Wars had been lived in, battered, rusted and shot with errant blaster fire.

But here's what's easy to forget until you put the film up against the most famous sci-fi or adventure movies of any era, from The Matrix to Avatar. In every other effects movie you can make an educated guess about the year it was made, because of links (however tenuous) to our own history. Lucas completely unshackled Tatooine, the Death Star and Yavin from the universe we live in and employed no such time-specific effects or visual (the only hint of its late 1970s origins are the lush and shaggy hairstyles).

He avoided looks that were anchored to cheesy animation or some piece of software destined to be overthrown by a better method. As a result, Star Wars' visuals stands up against any other science fiction film made since and has yet to be surpassed. It's, as they say about so many movies (a compliment which seldom truly sticks), timeless.

The anti-Star Wars camp is by now a long-standing industry in its own right, but in this case we can all believe the hype. It really is the movie that spawned the new Hollywood, and most of the time – whether we're a director with $200m to spend or a kid sitting down in a cinema seat – we're all just trying to relive the moment of that Imperial star cruiser roaring overhead over and over again.