By now, the story of Avatar is well known: James Cameron, who, along with George Lucas, has done more to revolutionize the moviegoing experience than any other filmmaker during the past quarter-century, began writing the sci-fi epic in 1994 and has been developing the photo-realistic 3-D technology necessary to realize his ambitious vision since the 1997 release of Titanic. After postponing the $200 million project on several occasions, his much-anticipated tale of human imperialism on an alien moon is due Dec. 18.

For those lucky enough to attend “Avatar Day” – an unprecedented promotion during which 16 minutes of the movie were screened for fans on 342 screens in 58 countries – the curtain was pulled back just a little, enough for six scenes and a closing action montage. Did the presentation live up to the hype?

First, a quick recap of what we learn. After a cordial welcome from Cameron, his selectively cut footage – all from the first half, he warned, so no spoilers – introduces us to wheelchair-bound Marine Jake Sully (Sam Worthington, of Terminator Salvation), who has just arrived on the Pandora moon for a special mission. “You’re not in Kansas anymore,” Col. Quaritch (Stephen Lang, whose tough talk seems awfully familiar) observes, and soon afterward we’re whisked off to an operating table, where Jake is prepped for integration with his Na’vi avatar.

The Na’vi, whom you might have noticed in the popularly downloaded two-minute trailer Cameron recently released on the Internet, are nine-feet-tall humanoids with navy blue skin and long tails. They inhabit Pandora peacefully, even as human soldiers are being genetically modified – to what end? – to match their likeness.

We next see Jake, comfortable in his Na’vi skin, braving a fully animated forest overrun with savage beasts. He meets a girl, a native Na’vi named Neytiri (Zoë Saldana, of J. J. Abrams’ Star Trek), and though sparks don’t fly at first sight, hints of a possible romance are obvious. Before long, she’s teaching him Na’vi customs – among them, wrestling what appears to be an oversized pterodactyl into submission and taking flight clinging to his neck. Harmony reigns. But the closing montage, which undoubtedly left all in attendance wanting more, suggests conflict impending.

And the verdict? Let me first say this is not a review of Avatar, merely observations gleaned from what amounts to an extended trailer on a towering IMAX screen. From the looks of it, Cameron has spent his money wisely: The Na’vi, who are seamlessly assimilated into one live-action scene with real actors, are convincing in a way so many CGI concoctions are not. (You hear that, Hulk?) In 3-D, the sequence in which Jake soars down a cliff aboard his new flying partner is breathtaking, and the landscapes Cameron has created are precisely defined.

The forest beasts, on the other hand, seem slightly less real, though not enough to distract from the action. My biggest complaint, one common to big-budget spectacles like Avatar, is that Cameron’s dialogue seems uncharacteristically pedestrian – not on a par with the uninspired babble of Lucas’ latter-day Star Wars trilogy, but close.

Will Avatar be the most breathtaking moviegoing experience in history, as the host of our screening boldly predicted? I hope so. Based on such a tiny appetizer, it’s impossible to know how the full-course meal will go down. But “Avatar Day” proved one thing: The hype is justified.