Basic plot: A greedy corporation has come a long way to mine Unobtainium (yup) on the planet Pandora. Earth, we find out later, is no longer green and in desperate shape. They need the Unobtainium for unspecified purposes. In the way are the natives (The Na'vi) and the rich and beautiful (but deadly) jungle life. They bring with them a powerful military, mechanized and ruthless. The atmosphere is poisonous to humans and the jungle animals are extremely dangerous... if you don't know how to handle them.
The base also has scientists (led by Sigourney Weaver) to understand and negotiate with the Na'vi. They have created Avatars, mindless beings in the form of Na'vi, that scientists take over in order to deal with the Na'vi on their own level. Avatars are very expensive to make, and can best be used by the humans they were built for and look like.
Into this mix comes Jake Sully. His twin brother was a scientist who spent years training for the mission, who was shot in a robbery just before he was sent. Jake is a Marine who was also shot up, becoming a wheelchair-bound paraplegic. Jakes genotype is a match for his twin's Avatar, and he is persuaded to go to Pandora. The scientists don't like Jake at first, but the military likes having one of them to spy on the scientists. Which he does.
To the surprise of anyone who has never seen a movie, the Na'vi really appreciate that a warrior is being sent by the Sky People. Jake meets and falls in love with one of the Na'vi even though her brother keeps trying to kill him. Eventually, they accept him, and he learns to appreciate them.
At first, the military follows orders and helps the scientists and slimy corporate shills, but when that doesn't work out they just bust loose and start shooting.
The film is gorgeously rendered in 3D, with writer/director James Cameron building new techniques to get the cgi Avatars to move like their human actors. Mostly, the 3D is used in small but effective ways. But the action is so quick that it sometimes beat out persistence of vision and blurred. I don't know how it would be in regular 2D; you'd lose much but keep some as well.
All through Avatar, I kept thinking, "Haven't these people read science fiction? Didn't they learn anything from Vietnam or Iraq? Haven't they seen Bambi?"
The clash between Heinlein's Starship Troopers and Anne McCaffrey's Dragonriders of Pern is cliche'd. A real expedition with this much riding on it would handle everything better. For how much time and money they corporation has spent on the project, they screw up the most important part: Mining the Unobtainium (why don't they just establish a base nearer some other site?). The military action is stupid (why don't thy use rockets, drones or Agent Orange?).
Like Bambi, the evil hunters are out to shoot anything that moves and the forest creatures react. Unfortunately for them, Pandora's creatures are not quite so gentle. At some point the fight was closer to Revenge of the Jedi. Interestingly (to me), Avatar is a post-post-9/11 story, where the soldiers are the villains. Haven't seen that in a while.
Ultimately, Avatar is Dune in the jungle: Pandora has something very valuable to the invaders who have an unstoppable army. The Na'vi recognize, pretty quickly, an outsider as having potential to understand their world, which he does by riding a worm, er, dragon and forming a bond with it. This convinces the Fremen... er, Na'vi that he's worthy. The newest addition to their people then leads them against his former affiliation.
At least Dune got the economics right: What should have happened is that the Na'vi make a deal with Earth where they will supply Unobtainium for a hefty price, and they will be left alone. The way it ended now pretty much guarantees the whole planet will be nuked and/or deforested. A non-used cliche is that the Unobtainium is necessary for Earth's survival (why?) but is also essential to life on Pandora. I'm just as happy Cameron didn't descend into this, but a little more about why the mineral is only on this planet (and how they found it) would have helped to flesh out a thin story.
Avatar is for the short attention span crowd. Few long shots, little exposition, lots of movement and emotion. Advantage: Got a lot in (there's a reason no one's done Dune right). Disadvantage: The movie seems hollow at second glance, with background and motivation driven by cliches. Not a good thing when you're trying to make a groundbreaking movie.
One of the unexplored bits of business was the Avatar technology itself: Do they grow them or construct them? Can they have children? Back on Earth, can any paraplegic with money get one?
Will Avatar be Tron: A groundbreaking movie where advances in technology come so quickly that it's dated almost instantly? Will Avatar be Blade Runner: A beautifully crafted movie that doesn't hold up to much scrutiny? Will Avatar be Wall-E, an eco-friendly film that will be remembered fondly despite how it manipulates and relies on cliche?
Or... Will Avatar be 2001: A Space Odyssey: A brilliant movie that advanced cinematic technology and remains a high-water mark in science fiction storytelling? Will Avatar be Star Wars: An action packed good-guys-vs-bad-guys with a rich back story that virtually creates a genre?
Got me. I suspect that Avatar will make its huuuuge investment back and other filmmakers will have to pay attention to the new technology. Whether this will make better films remains to be seen. My one prediction: Within a few years, it will be significantly cheaper to do. Watch for Avatar-like home gaming systems within a decade (replacing Wii).
I think Avatar is a good movie, one any sf fan should see eventually. The advances in technology work okay but feel like a work in progress. And be aware that it is NOT a kiddie flick. Despite its PG-13 rating, it's very violent and bloody.