So have we finally got round to saying some of the the things that can make a movie bad. To me, the biggest single thing is whether the movie contains moments where for some reason this 'suspension of disbelief' is broken (And if you want the word 'wilful' in there, be my guest.) The moment can be due to clunky dialogue, or something happening that is impossible within the agreed 'world', or many other things. The important feature is the movie fails if that 'hang on a minute' thought hits you. Occasionally a move may be good enough to recover but usually one event is enough to finish the thing off.

The second thing, rather less important, is how you feel afterwards. Changing media, I find Stephen King stories almost all have this effect on me. I can start reading one, and find it sufficiently gripping that I read all the way through quite avidly then immediately I've read the last paragraph I think 'why on earth did I waste two hours [or whatever] reading that rubbish?'

For me Avatar fails on both counts. Up to now we have concentrated on why the Na'vi don't have six legs. But that could have been a lot less jarring had some other creatures had four as well: giving them 6 limbs was not the only solution. It was the uniqueness that did it for me. But that six-limbedness was again a somewhat lazy way of emphasing we are on a different world. And while making the Na'vi very human to make it easier for us to relate to, that's also a sign of laziness in the script to me. After all, "Beauty and the Beast" manages to make us accept that the visual appearance of the creature need not be the only relevant factor. But ok, let's make them look very human: why do the female Na'vi wear T-shirts for heaven's sake? Why not bare-breasted or burka, or dress in any fashion at all apart from late 20c America? The answer lies much more in box office profits, than in making a good film. Let's not challenge the audience...

Then let's get onto how you feel afterwards. LH for one clearly gets a lot out of it, but for me the sheer naive simplicity of it all made me feel it was a waste of time. What redeeming features do the humans have? What objectional features do the Na'vi have?

Don't get me wrong: I don't think all films need to be 'improving'. "Some like it Hot" is one of my favourites, but it is hardly an intellectual treatise. No, this additional check is more likely to come into play if the actual film was not especially entertaining in its own right.

The final claim for Avatar people make is the great visual effects. While I completely agree on this today, I still wonder. Look at the mechanical bird in "Mary Poppins" during the "Spoonful of sugar" song; or the back projection in virtually every driving scene from films of say the 50's. What was the top end special effect of the time has a bit of a tendancy to look naff fifty years down the line. When it does, the film normally has to stand on other merits. But not always: we can admire the Harryhausen animations today, even though they look well below modern standards and the rest of the films are not usually up to much. So I'm undecided how Avatar imagery might be thought of in 50 years time.