Heath Ledger’s last role is not his greatest

Terry Gilliam's The Imaginarium of Dr Parnassus was always going to be known as the film where Heath Ledger died during shooting. While other directors might have given up and started again if their star had been found dead from an overdose of anti-depressants and sleeping pills halfway through filming, Gilliam went ahead undaunted.

Through a combination of luck and gargantuan ambition, the former Monty Python member turned film-maker had plenty of experience of tricky finishes. His solution on this occasion was to rewrite the script and enlist a trio of Hollywood A-listers, ­ Johnny Depp, Jude Law and Colin Farrell, ­ to play different incarnations of Ledger's character, Tony Liar.

The film, finally opening in the UK this week, centres on a travelling roadshow troupe. A 1,000-year-old storyteller called Parnassus, played by Christopher Plummer, has made a pact with the devil, trading immortality for his daughter Valentina when she reaches 16. (Tom Waits plays the devilish Mr Nick and model Lily Cole plays the girl.)

Desperate to reverse the deal and save Valentina, Parnassus enlists the help of the mysterious newcomer to the troupe, Tony Liar. This snake-tongued charmer was inspired, Gilliam told the Times recently, by Tony Blair. "Not based on him. But certainly Tony Blair angered me enough with his silver tongue and his ability to convince everybody that what we were doing was good and right."

Gilliam's film is not for everybody - but then neither were Time Bandits, Brazil or Fear and Loathing in Las Vegas. For Ledger's fans, it is an interesting curio. He is good, as he always was, but it's not a part that can be compared with Ennis Del Mar in Brokeback Mountain or the Joker in The Dark Knight and anyway the film is very much an ensemble piece.

Other actors picked out by the critics for special mention have been Lily Cole, who is ­ "immensely sexy and showing far more promise than you might expect from a supermodel", according to one smitten reviewer - and Johnny Depp, the best of the stand-in trio. As for the veteran Plummer, there's even been talk of a possible Oscar nomination.

WHAT THE CRITICS ARE SAYING:

Nigel Andrews, Financial Times: "Oh dear, even the title screams 'Terry Gilliam'. Lay on the rococo wackiness; gild all available lilies; let a thousand fantastications bloom. Some of us think Gilliam should be forced to sit in a bare room for a year directing Samuel Beckett plays." (Verdict: two stars out of five)

Ryan Gilbey, New Statesman: "It's typical of this ramshackle director that the film's neatest joke should be buried in its small print. Midway through the picture comes a curious set piece, part Monty Python and part Michael Clark, featuring a troupe of nightstick-wielding bobbies in miniskirts and fishnet tights. Not until the end credits roll do we learn that their big musical number, "We Love Violence", was performed by the Sir Ian Blair Memorial Choir.

Wendy Ide, the Times: "Ledger plays [Tony Liar] more as an elaborate con than a character - he's a sleight of hand, a sly diversion constructed from smoke and mirrors and a touch of eyeliner. He looks great, but beneath the surface you would be hard pressed to find much of substance. The same could be said of this enthralling but flimsy bauble of a film."

Tom Huddleston, Time Out: "It's telling that Parnassus, an unsubtle proxy for the director, never recognises his own culpability as his audience's interest dwindles: it's modern man's refusal to open his mind, not the artist's unwillingness to connect, that dooms the Imaginarium. It's unlikely Gilliam's own, undeniably brilliant career will be revitalised by this rambling, undisciplined and indulgent piece of work."

Olly Richards, Empire: "Ledger is very good - all Jack Sparrow eye-aerobics and Chuck Jones-ish japing. But it would be wrong to compare it to his superlative work in Brokeback Mountain or The Dark Knight. It's those roles that will serve as his epitaph; this is the full stop."