Having your lead actor die halfway through filming must be the worst thing to happen to a director – other than die themselves of course. As was reported worldwide, this is exactly what happened to true visionary Terry Gilliam, when Australian actor Heath Ledger died last year at the all too young age of 28.

But embodying the adage ‘the show must go on’, three A-list actors (Johnny Depp, Jude Law and Colin Farrell) agreed to appear in the film as Ledger’s character, in order for the film to be finished. Despite the tragedy surrounding it – and no doubt continuing to do so, as it will always sadly be dubbed as Heath Ledger’s last film – Gilliam is arguably at his creative best.

A curious troupe of performers transport their portable theatre by horses, through the modern streets of London. Their leader is the quite ancient Doctor Parnassus (Christopher Plummer) who has the ability to create the imaginarium, which allows others to travel to magical places, for a small fee of course.

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Despite the valiant efforts of his daughter Valentina (Lily Cole), Anton (Andrew Garfield) and Percy (Verne Troyer), business is far from booming. Their luck appears to change however, when they rescue a man hanging from beneath a bridge. The stranger (Ledger) claims to have lost his memory and has no idea who he is. Whoever he is, he certainly has a charm that appeals to the ladies, as he manages to drum up business for the troupe.

However, this band of performers is hiding its fair share of secrets. The doc, for instance, is on friendly terms with Mr Nick (Tom Waits) – who is simply the devil by another name; not only that, he manages to get sucked into wagers with him at the expense of the souls of others. It also appears that the latest addition to the troupe may know more about his own identity than he’s prepared to let on.

And so the scene is quite literally set for yet another sumptuous feast for the eyes, as served by Gilliam. As with most of his films, the devil is most certainly in the detail. No other director paints a cinematic picture like him. His vision is even more remarkable when you consider the film cost roughly $30 million to make, which is about $60 million less than it costs to make the average Hollywood blockbuster; and compared to any of Gilliam’s films, boy are they average.

The premise of the story is like a Python sketch falling into a Dali painting. Although the characters in the troupe are real, they already feel and look like figments of our imagination trapped inside the wrong world. And although using a mirror as a device to travel from one world to the other isn’t in itself all that imaginative – or original for that matter – it works exceedingly well, particularly in its shabby, Blue Peter, home-made kind of appearance.

And besides the obvious trio of A-list talent standing in for Ledger, who all do remarkably well considering the circumstances, Gilliam does well with the casting. In some way, it would be a disservice to Ledger’s legacy as an actor to say that it’s his best performance. The truth is, it’s not. However, he does help convey the sense of it being a real team effort, and by no means lets the side down.

The true stars of the film however, are the older members of the cast. Despite Plummer mocking that Gilliam didn’t have much in the way of choice when casting a mature actor to play the elderly Parnassus, he gives quite possibly the best performance of his lengthy career.

His foil in the film is Tom Waits, who’s day job may well be as a singer, but has built up an impressive CV over the years with his film work, especially for director Jim Jarmusch. Waits is striking as the Mr Nick, making his devilish character have a remarkably playful side. When he and Plummer on are on screen, even the impressive scenery they find themselves in, can’t detract from their magnetic relationship.

A worthy mention also needs to go out to two of the younger members of the cast as well. Relative newbie Cole does well enough as the love interest Valentina, but Garfield especially, shines – literally and figuratively – as the love-struck Anton.

The Achilles’ heel of the film, as with most Gilliam films, is the script. It’s adequate at best, without ever matching the brilliance of the visual experience. This means that some of the dialogue is a little on the clunky side, but considering how much Gilliam gets right, it’s not too difficult to forgive the script’s weaknesses.

With The Imaginarium of Doctor Parnassus, Gilliam reinforces his position as being one of the most creative and visionary directors of all time. Every time an audience turns up for one of his films, they are consistently guaranteed an adventure worth watching. That’s a statement that very few directors, past and present, can live up to.

If cinema is all about escapism, then this film is about as close to pure cinema as you can get.