It's always the case with a film by Terry Gilliam, that you never really know what you're going to get. You don't know what you should expect, and sometimes you barely know what you're paying to see. For the longest time I had no idea what this film was actually about, or in what time period it was set, or anything.
Much of the chatter around it, naturally, surrounded the death of Heath Ledger (who gives another great performance here, proving like The Dark Knight did, that a truly great acting talent was taken too soon). Trouble does tend to follow a Gilliam film, and such tribulations are well documented, but these actually add to the flavour and occasion of a Terry Gilliam film.
The fact that he is still making movies, even after all his filmmaking career has been through, is just really inspiring in itself.
To respond to a couple of oft-talked about things, the transition from Ledger to Depp/Law/Farrell is never jarring. It makes total sense in this world, and is never confusing. At times you'll even swear that his three replacements actually resemble Ledger.
Another thing is the Imaginarium itself. Mark Kermode spoke about how the Imaginarium itself doesn't feel weighty enough - much of it being CGI - and this is indeed the case. After a moment that, for me at least, really made an impression (the first opening of the Doctor Parnassus sideshow outside a London nightclub), a scene that really shows off the weight and sheer size of the horse-drawn show, the world of the imaginarium itself does indeed feel weightless.
It's like a more serious, but no less weird, big budget version of Gilliam's Monty Python cartoons. It's wonderfully daft and quirky and colourful and actually, quite confusing - but in a nice way. This is indeed, as has previously been talked about by others, a film that has to be seen more than once to understand what you've just been shown (and perhaps even then you won't get everything). Although, most Gilliam films are like that, so it seems.
But is the weightlessness a bad thing? Certainly, I don't see how it could have been achieved practically at all, so it wasn't a bother to me.
This all said though, I still have no idea quite what to make of The Imaginarium of Doctor Parnassus. However, the fact that it has remained in my mind, swirling around in there, is testament to it being a bloody good film. If only I could tell you exactly why...