This is the film that brought classical styles of music back to the cinema, and set the pace for nearly every other special effect movie, since (there's also a large range of novels related to the series, about more than just these films). They set up their own special effects units, “Industrial Light and Magic”, which have been responsible for producing the effects for an awful lot of other films, ever since, and eventually set up “Skywalker Sound”.
The films began at episode 4, in the 1970's, and was very impressive for it's day. Even now, it's still impressive; both in the (very well done) complex effects, and the stunning views. It's one of the few science-fiction films where you can get a good, long, hard, look at an expansive scene; rather than just a glimpse (so you don't notice how badly done the effects are). The prior episodes were produced as prequels in the 1990s, and really aren't anywhere near as good.
If you're not a science fiction fan, I really suggest that you start off with episode four (the first film that to be produced), as it's a lot of fun, more than just being a science-fiction film, and isn't anywhere near as childish as episode one. It, like the others, is a film with various concurrent plots. It's a political film, with the good guys fighting against evil oppression. Yet the bad guys are charismatic enough that you don't hate them, outright. And it's a bit of a romance film, with a princess being rescued by a poor farmer. It's also a classic war film, with some spectacular dogfight scenes between space craft (all the more impressive, when you realise that they're not done using computer generated effects), and a few sword fights. There's also quite a bit of sly humour, and most of the film is acted with a sense of fun (it's quite clear that all the actors spent a lot of time together, they tend to act like they're a family—a family in the days before all TV and movie families were dysfunctional and hideous).
The main evil character, Darth Vader, is the central character to the entire series. He's a fallen hero, who succumbs to all that's evil, but eventually is redeemed. In the first film, we see him as the most evil man in the galaxy, eventually learning something of his past. By the last episode, we know most of what we need to know about him, and discover someone far more evil (the Emperor), and Darth's “saved,” though only just before his death. In the prequels, filmed many years later, we see him as a child, a slave who is freed; then as a bit of a petulant youth, who is destroyed after the brutal death of his mother.
Another thing that was played upon, with the more recently done prequels, is that many of the characters that come together in episodes four, onwards, actually had relationships with each other in their childhood, but don't seem to realise it. We see the parents of the enemies, when they were still children, getting along with each other. And various scenes showing how certain characters got to be resentful, and grew up to become mercenaries. For example, Boba Fett is a bounty hunter, with a fairly big role in the later films; in the earlier films his father (Jango) is the one they clone for the clone army, and his son (Boba) sees his father beheaded in battle by the Jedis. And there's Guido playing with Anakin, as children; later in Episode 4, he's shot by Han Solo, for demanding Han pay back a debt to Jabba the Hut, at gunpoint.
Frivolous, and juvenile. Both in the dialogue, and much of the story. It's clear that they aimed this film at young children, and really dumbed it down. It was about half way through the film before they started speaking in a more adult dialogue. The music's, also, not a patch on the first three films. Nor are the effects, with some rather poor CGI (computer graphic imagery), instead of using actors for some of the robots, and space ship fighting scenes. It follows the modern trend, of films that look more like video games, than movies.
The films starts with a trading federation blockading a planet, as part of the Emperor's plans for the beginning of the end of the Jedi Knights. The Queen (Amidala) escapes, ends up stranded on the planet Tatooine, becoming reliant on the child Anakin Skywalker (later to become Darth Vader) to win a race so they can repair their ship, and escape to the republic, to try and do something about the blockading (and invasion) of her planet. Anakin is freed from slavery, and joins them.
She returns home, has a few battles, and Obi Wan (finishing his apprenticeship), loses his tutor during a three-way sword fight with the Emperor's side-kick, Darth Maul. They manage to quell the invasion, and the blockade, after a huge battle (using not-so-special CGI effects); and young Anakin is to become trained as a Jedi; though not without reservations. He's seen as fulfilling a prophecy, as one who'll bring balance to the galaxy, but not before being an incredibly destructive force. Though they only sense that he's a danger, they don't realise why.
Anakin is now a petulant youth, angry with authority, without patience, and an apprentice Jedi, to Obi Wan. He's assigned to protect the Queen, though he's smitten by her, with a love that just wasn't meant to be.
In the middle of his assignment, he feels that he needs to go looking for his abducted mother. Queen Amidala goes with him, and he rescues her, just before she dies. Anakin takes this very badly, and starts down the path to the dark side (evil).
In the meantime, Obi Wan is investigating the secret development of a huge army, grown from clones of a bounty hunter (Fett). While the trading federation is developing their own droid army for taking over the republic, to become the evil empire (in the later films).
The two armies end up fighting each other, and although the clones are victorious, we see them returning to the republic as the army that'll eventually be their oppressors as the Empire. The leader of the republic happens to be the future evil Emperor, though we only work that out for ourselves by deduction, rather than it being explained to us, who has other plans for the clone army that he secretly arranged to be developed.
After the opening titles, and prologue, the film stars with a huge ship zooming over the screen, chasing after another. In which is a princess escaping with the plans for an even bigger ship, the size of an entire planet, known as “The Death Star,” capable of travelling through space, and destroying entire planets in one blast (the original destruction of Alderaan by The Death Star, rather than the meddled with version in the re-releases of the film, looked much better).
She's captured, but sends some droids off with the plans, who end up on the planet Tatooine, looking for a Jedi Knight (Obi Wan Kenobi), to try and free the republic from the oppressive evil empire. They find him, a few people get killed, and they (with some other people, Luke Skywalker, and Han Solo), escape the planet just in the nick of time.
When they arrive at their destination of Alderaan, for where the plans were intended, they find the planet has been obliterated, and end up being captured by The Death Star. They eventually escape, but not before Obi Wan is destroyed in a sword fight, and reach the rebel alliance with the Death Star plans. The rebel alliance sets out to destroy The Death Star, and after a long battle, manage it. The film ends in a big celebration (with a some lame cardboard cutout people inflating the numbers of the audience, instead of a large group of real people).
The rebel alliance is in hiding on a snow covered planet, regrouping to do battle with the rest of the evil empire, but are discovered. They're attacked, but most of them manage to escape.
Luke heads off to be trained as a Jedi Knight, but breaks it off when he realises his friends are in danger (they've been captured by the empire), and he sets out to rescue them. In the process, Darth Vader reveals that he's Luke's father. Luke gets disillusioned, but eventually decides that he's going to turn his father from the dark side, and that's how they're going to save the galaxy from the evil empire.
In the meantime, Han Solo has been captured, and encased into a huge slab of metal (in suspended animation), and given to a bounty hunter.
Luke sets out to rescue his friend, Han, and succeeds. They discover another Death Star is being built, an even bigger one, and set out to destroy it before it's completed. A large battle fleet is assembled, but it ends in almost a Mexican stand-off, when they discover that the Death Star is already armed. It's not complete, though, and relies on being protected by a force shield powered from the planet, below.
A team sets out to destroy the shield generator, doing battle on the planet with some of the imperial guards, and joining forces with some little teddy bear type of characters native to the planet. While this is going on, the space ship dog fights are carrying on overhead; and in The Death Star, Luke (captured from the planet below), is sword fighting with his father because he won't be turned to the dark side by The Emperor.
Winning the sword fight, the Emperor decides he'd rather kill Luke, and this is where Darth Vader turns. He rescues his son by destroying the Emperor, at the cost of his own life, at much the same time as the rebels destroy the shield generator, exposing The Death Star to attack.
It's destroyed, and with the death of the Emperor, too, the empire is at an end.