I'd better tell you about this film Mirrormask quick smart, because it seems like the sort of film that'll drop out of its limited distribution in about two weeks- catch it while you can.
Mirrormask is, as anyone with even a scintilla of decent popculture knowledge will already know, the brainchild of Neil Gaiman and David McKean, both of Sandman fame. And that's basically all you need to know- the film is very much like what would happen to you if you fell into a copy of Sandman: The Collected Dust Covers and wandered around randomly for an hour (sometimes you could even see the paper it was drawn on). It'd be pretty amazing, but you'd have trouble explaining exactly what you saw to anyone after you got out.
If you come looking for a plot, well, there's no much here. A girl named Helena (who is quite appropriately named as she looks very much like a young Helena Bonham Carter) wakes up in an odd fantasy world (cleverly comprised of the drawings she makes on her bedroom wall) that she takes to be (and may well be) a dream. So far, so Alice in Wonderland. But what Helena slowly realizes is that she's merely traded places with her evil counterpart, who is living it up in the 'real' world (a beautifully shot Brighton) by, er, smoking cigarettes, making out with punks and fighting with her dad.
If this sounds like a bit of a plot to you, well, this is all hinted at, but the majority of the film is actually just Helena wandering around her dream world. The problem with the dream world, as incredibly well visualized as it is, is that everything that happens there seems artibrary and without consequence. They go from A to B to C (and at each pick up a new 'quest point', something Gaiman has railed against in the past), but there's no sense of any true connection outside an author's whimsy or an excuse to show one more imaginative setpiece.
And that's really all there is to this film: it's a long parade of really lovely images (it actually reminded me a lot of The Cell on that level). And on that basis I really enjoyed it and if you love the artistry of comics or surrealist art I think you'd find it a real kick on that level. If you're looking for substance, look elsewhere. You get the sense that there's some kind of allegory about teenage angst and growing away from your parents, but it's so lightly glossed over it seems almost an afterthought (it clearly aspires to be a modern-day Labyrinth, but unfortunately falls short in both the thematic and raw wonder departments). It's frustrating because you're not really sure who its aimed at. Kids will find it utterly confusing and adults see that behind the confusion there isn't any meaning. Maybe it was made for the ADD generation where all that matters is the moment, and a procession of cool images will suffice.
And I don't say all this as criticism- I think that the film is perfect for what it is- a jaunt through The Dream. If they ever do make a Sandman movie, this is how they should do it. But there are a lot of trips into dreamland that manage to have both plot and emotional resonance, and I think this...I think this taps into the new style of film-making, where anything you can imagine can now be created. But imagining cool stuff isn't enough to make a truly great film- for that you need a solid story, with consequences and characters you can connect with.

Having been meaning to get into Sandman comics (and graphic novels) and Neil Gaiman in general for ages, but not having gotten round to it yet, I haven't a clue about any of your references, but it sounds like an interesting film. I should get round to the Neil Gaiman thing pretty soon really shouldn't I...
Adding to what Dan said, it is worth seeing for the visuals alone which are stunning.
The story is their, but it is quite simple. Very never ending story ish. I wanted to ask the kids in the cinema what they thought.
And the movie could also be enhance, with popcorn.
saw the comment & wanted to add a bit...
i've seen the film twice now, which helps.
mckean's artwork has always been darkly surreal to me...before reading some of the gentler stories w/ cages, a lot of the work i had known from mckean came from skinny puppy album covers.
the first time, i did feel like whatever they were trying to say, was relativly unclear & foggy, and a lot of the story was lost in the imagery.
it should also be noted, the visuals were produced by the jim henson company, and so some of the stylistic feel for me comes from remembering films like labrynth + the dark crystal.
sometimes w/ more graphically intense movies these days they end up feeling more like a video game than a movie-the new star wars had a lot of that feel. that, coupled w/ poor dialog, left me feeling like the soul had been sucked outta them (and lucas in the process).
favorite bad new star wars moment: beginning of episode 3, big fight:future darth vader vs. christopher lee. vader cuts off his arms and beheads him.
next line by obie wan: anakin! you've killed an unarmed opponent!
does he realize his writing is this off?
after 2 viewings of mirrormask, i feel like whatever story is going on is still a bit unclear, but it also improved for me on a 2nd viewing. there's a lot more nuance, subtly, and cheeky english fun going on. things to make you laugh during somewhat spooky imagery. i'm also hoping that mckean is able to produce more through completion of this project. seeing mirrormask as well as hitchhiker's guide, gives me hope for the jim henson's company continuing tradition of a combination of puppeteers & cg's.
so yeah, good try, i'm looking forward to the next one.
Although the Jim henson company produced the movie, I thought the visuals were all Mckeans?