Well, the BFI IMAX was packed to the rafters (and those rafters are very high, folks) with fans eager to see the epic imagination of James Cameron, no doubt soon to be crowned King of 3-D. But what can be gleaned from 15 minutes of footage? Can you really get a sense of what might unfold in a few months time? Probably not, but hey, let's give it a bash.

First thing to note: it's incredibly impressive. Visually speaking, anyway. It all kicks off with James "Jim" Cameron (in 3-D!) introducing the footage. In a baseball cap. How quaint. But then we get to the meat of it: a ship full of soldiers orbiting Pandora - pitched somewhere between a tropical paradise and jungle of death. He strolls up and down between the ranks of soldiers, shouting fear into their faces in true military style. Then, up rolls wheelchair-bound Jake Sully (Sam Worthington), who's about to be placed inside the consciousness of his very own Na'vi alien body.

Then we get a scene between him and Sigourney Weaver, or Grace, the resident Doctor onboard. As Jake goes into the Na'vi, we see his elation at being able to move, bounding around like a crazy blue man (who's 3 metres tall, by the way) before bursting out the lab in a fit of physically-enabled glee. It's kind of cute, like an over-excited giant blue puppy, but there's no real sense of emotional engagement. And yeah, he's blue, but the 3-D hasn't really kicked in yet.

Then we hit Pandora. And boy, it is big. Luscious CGI landscapes stretch out across (and back into) the screen, a vast panorama of an unknown planet: here is Avatar's triumph, perhaps, giving us a sense of something brand new. This isn't no Tattoine desert, or Beckton backlot - this here is a foreign place. And it's mostly fake and computery. Don't get me wrong - it's good fake, and that computer is put to good use. Is it wrong to miss the nostalgic feel of a constructed set?

I promise you this: if you do, you'll soon stop once the characters start chasing each other through the woods - one word for you 3-D nuts: foliage. So much foliage. You soon get used to Pandora's appearance. It's pretty. Really, really pretty. Speaking of which, in comes our female character, and a brief little exchange between her and Jake leads to a bit of kissing. Here's that romance Cameron was so keen on; the emotional core to reign in the audience and get us connected to his creation.

But there ain't much in the way of warmth here. Sure, they're big, blue and bleeting sweet nothings at each other ("You have a strong heart"), but I'm not feeling the love tonight. Luckily, though, the scene ends and we cut to some sequences with more bizarre beasts and strange animals (the creature design is crazy and refreshing - there's a real sense of a different evolutionary path on Pandora). That said, we still get the standard man-mounts-bird-and-flies-off-a-cliff moment. Even Ice Age 3 and Harry Potter had that. Then a brief montage of loud machines, angry gunfire and some frantic running, and it's over. The title comes up. The screen goes to black. The audience applauds.

So what to take away from the footage? Well, the effects are good; the CGI is solid. Cameron's creative skills with computers know no bounds. But with slightly corny dialogue and some dubious romantic interest, it might be a bit much to expect Titanic 2: Welcome to the Jungle. And without that core connection, will this blockbuster be any more than blocks being busted - even if they are very pretty blocks. The action, in fact, is superbly done (take note Michael Bay), not at all blurry or confusing, but dynamic and exciting.

Now, of course, the main focus: the 3-D. Does it really add anything? The forests are quite immersive, and staggeringly beautiful, but would this beauty be any less striking in plain old 2-D? I'm inclined to think not. The 3-D didn't seem to add much to the already awesome experience of watching one man's spectacular vision projected onto a screen the size of 5 stacked houses. But that just might be the point. Was the technology so impressive, so subtly employed, that it didn't hamper the viewing experience? Without some cartoon character waving a stick in my face, did Cameron's stereoscopic skill work its magic unseen? Maybe so.

Sadly, these things will only be certain from the full-on feature film - when characters will be more fully formed and a narrative will be constructed out of these pretty, memorable images. Until then, Avatar. Exciting? Hell yes. It's not quite mind-blowing, but it is very, very impressive.