There is really only one reason to watch The Imaginarium of Doctor Parnassus and it’s not for the story. Terry Gilliam has made a habit of making big, somewhat surreal films that are, as Mark Kermode puts it, properly cinematic. But he’s never actually made a film I want to see. I might’ve seen bits of his movies in the past – did he do the one with the time travelling helicopter? And I know I’ve got Twelve Monkeys on DVD somewhere because I remember it came in one of those DVD jewel cases that were briefly used in the format’s early days. I’ve not seen the one with the Baron whose name I won’t insult you by trying to spell or any of the other grand fantasies to have come from his colourful imagination and swum around in production problems and red ink until they achieve cult status and a semi-ironic following. The reason anyone has heard of Parnassus and would want to watch it is because of Heath Ledger. Don’t get me wrong, it’s not ghoulish curiosity. Not with me anyway. I’d not heard of Heath Ledger until he died so seeing his last work on this Earth doesn’t hold a creepy fascination to me. I’m interested in how a film can continue after its leading man has died. How can a movie cope with such a loss?

The Crow was almost finished when Brandon Lee was killed and they just needed a few CGI effects and a bit of editing to hide his passing from the finished product. Plan 9 From Outer Space didn’t have CGI – they certainly didn’t have computers or generators and barely had any images to speak of – so had to make do with a different actor and a sleeve over the face when Bela Lugosi died during the shoot. Parnassus was lucky – or as lucky as a film can be when its star dies – because Ledger had completed enough of the "real world" material for Gilliam’s brilliant plan to take shape. This is why I wanted to watch Parnassus – for a piece of directorial brilliance that surpasses even the hiring of Hamish Wilson when Frazer Hines got chicken pox and had to miss an episode of "Doctor Who and the Mind Robber".

I’m sure you know by now but if you don’t then this is how it’s done. Heath Ledger plays Tony – a man they find hanging from a bridge – who quickly inveigles himself into Parnassus’s travelling show. The centrepiece of the show is a magical mirror which people can pass through into a world apparently powered by imagination. Three times in the film Tony passes through the mirror – always with someone else – and each time he looks different. Same clothes, same hair, same beard and moustache but a different face. Specifically those of Johnny Depp, Colin Farrell and Jude Law. It works brilliantly. Because the mirror world is powered by the other person’s imagination, Tony takes on the appearance of how they see him. We all misremember what people look like – we know roughly and remember clothes, hair etc but never all the details. So Tony takes on different faces throughout the film and you don’t really notice. Indeed, if you didn’t know Heath Ledger had died, you could well believe this was how the film was meant to be. It’s that seamless.

Sadly, though, that’s all the film has going for it – an ingenious way of hiding a tragedy. The plot doesn’t really make a lot of sense – Parnassus is immortal and keeps making bets with the devil about how many souls each can win. Unwary people are lured into the mirror and a scenario plays out which either ends with them burning in the devil’s flame or being thrown out of the mirror (on a swing) in the throes of ecstasy. It would be fine if this was some kind of good versus evil tale but it isn’t. Parnassus lies to the people he suckers into entering his magic mirror and risks their existence just to win his latest bet with Old Nick. And he doesn’t really seem to care about this – all he cares about is his daughter and he’s been lying to her for her entire life. There isn’t anything evil about Parnassus – he’s just old, a bit bored and stuck in a life of shallow huckstering that he doesn’t really want anymore. I think we’re meant to feel sorry for him but I didn’t. He isn’t a likeable character by any means. He plays the world-weary immortal a little too well. He’s seen everything he wants to, done everything he wants to and now he’s long past the point of death but carries on mumbling and stumbling around London.

Once you get over the curiosity of seeing how the Ledger situation will be dealt with there is nothing for you in this movie. The imagery is well realised but entirely hollow. It’s meant to be a film about imagination but to me imagination has a purpose to it. It tells a story or creates a fantasy world. Here it is more akin to a dreamscape where random things happen and the laws of physics need not apply. Take the middle aged woman who is the first of Parnassus’s triumphs in this round of him verses the devil. Her imagination creates a world of giant shoes and a gondola. Yes, it can be taken as a bit of a commentary about the post-Sex and the City world in which we live but it is hardly a triumph of the human imagination. Just because you can create giant shoes and a surreal journey betwixt and between them doesn’t mean you should. Parnassus’s background origin story montage thing (we get one of those) has him proclaiming the power of stories but why then does his imaginarium create dreams rather than stories? It makes no sense within the film or in isolation.

Take away the film’s back story and the need to do something imaginative to hide the death of its star and you’re left with a film that looks good but doesn’t make any sense. It feels like it wants to be deeply symbolic but without bothering to work on any conscious levels. The story is nonsense, the internal logic is all over the place, imagination is confused with surrealism, none of the characters is entirely likeable or sympathetic, the jokes aren’t funny and it doesn’t have sort of consistency. I admired the way they finished the film when most people would’ve given up and I did sort of fancy Lily Cole in places but it can’t save the film. It’s a depressing dirge of grime and colours which I’d imagine is even more depressing if you liked Heath Ledger. It’s a film that will live on for decades – one where everyone will know what they did but few will ever have actually bothered to see it.