Generally, when we talk about a movie that changed the world, we’re talking about it in past tense. “Star Wars,” “The Lord of the Rings,” “Toy Story,” these were all films that we went to see and realized afterwards that we had just seen something new and exciting. So it has to arouse suspicion when a film comes along with the ballsy tagline: “Movies will never be the same.”

James Cameron (“Aliens,” “Titanic”) spent 15 years of his illustrious career and $300 million of Fox’s money to make “Avatar,” a sprawling sci-fi epic set on an alien world in the distant future. The buzz around the film has largely been centered not on the story or the performances, but on Cameron’s use of new technology to make the film look and feel like no other before it. While the film is definitely different, and the movie magic gadgetry has been pushed into overload, what all the techno buzz essentially amounts to is a theater full of people watching a really, really expensive video game.

The year is 2154, and Earth is failing (imagine that, another movie about how we killed our planet). To compensate, a mega-corporation has colonized an alien rainforest world called Pandora, where rich deposits of a precious mineral called unobtanium (really?) lurk beneath the soil to save the human race through boatloads of cash. The problem: Pandora is inhabited by a bevy of savage creatures, and a civilization of blue humanoids called the Na’vi. The solution: former United States Marines called in to do mercenary work while the miners get their fill.

As part of the corporation’s effort to make their operation easier, they allow biologists Grace Augustine (Sigourney Weaver) to attempt to infiltrate and befriend the Na’vi using avatars, test tube bodies grown from a combination of Na’vi and human DNA. Augustine and her team of scientists each have an avatar, grown to match their DNA, that they can “drive” while shut into a special chamber at the lab.

Enter former marine Jake Sully (Sam Worthington). After the death of his brother, a scientist on Augustine’s team, Jake is called in to drive his brother’s avatar (they have the same DNA, you see). Without any scientific knowledge, and with orders to secretly report to the ruthless head of security (Stephen Lang), Jake finds himself suddenly deep in a new world where he can not only walk again, but start over.

After getting stranded in the forest, Jake, still in his avatar, meets Neytiri (Zoe Saldana), a Na’vi princess, and is slowly and begrudgingly adopted into her tribe. As the pair grows closer, Jake is shocked to find that he feels more at home with the aliens than he does with the humans, and as the frustrated corporation begins to close in on the Na’vi civilization, he must choose sides.

It’s obvious that Cameron went to great pains to create this world well before the cameras started rolling. The Na’vi are a fully developed race, complete with their own language and customs, and a seriously cool way of becoming one with the earth. Likewise, Pandora is a fully-developed world filled with unique creatures and plant life that’s both a feast for the eyes and for the intellect. Even if it’s just a movie, the planet feels very real.

And the technology employed only adds to that realism. Using tremendous advances in motion capture technology, as well as new cameras that allow him to see the digital world even as he’s filming, Cameron creates a feast for the eyes, from a mountain range hanging in midair to a swarm of massive flying reptiles ridden by Na’vi warriors. And the best part of this visual wonderland is that you never see the technology on screen. Cameron weaves his new toy seamlessly into the background, so all you have to do is watch what he’s made for you. Trust me when I tell you that, as far as visuals go, this flick is packed with jaw-dropping moments of pure exhilaration.

Where the film falls short is its story. Cameron, who also wrote the screenplay, obviously has a lot to say here about the environment, the treatment of native peoples, the evils of industrialization and the like, but even amid all this new techno-wizardry and sci-fi loftiness, there are no new themes. There aren’t even new treatments of old themes. While it all looks amazing, what happens to Jake and Neytiri as their adventure unfolds becomes all too predictable, and the tale is so overstuffed that by the end of the two and a half hour experience you’re looking for a fast forward button.

And the performances: I honestly can’t say much, not because there wasn’t effort, and not because there wasn’t talent, but because whatever humanity these actors might have brought to the table was either scaled over by blue alien skin or slicked back with action movie cool. Everyone did their job, but no one stood out.

In the end I think the film’s rather brazen tagline is a very grand overstatement. I’ll be the first to admit that “Avatar” looks cool, and I’ll also admit that I can’t wait to see how much further they take this technology, but technology doesn’t make a movie, technology makes a shot. Movies that change the world have to have more than the flash and pop of special effects. They have to stir something in you, something you wouldn’t have otherwise felt, something that fills you with the endless potential of the human imagination. “Avatar,” for me, fell short.

Matt’s Call: It’s overstuffed and decorated with not a little self righteousness, but it’s still a blast to see. Take the kids to watch the alien magic, but be prepared to make a mid-movie pit stop. It’s a long one.