Bound to get the lion's share of media attention, the late Heath Ledger's final (uncompleted) performance in The Imaginarium of Doctor Parnassus is actually just one of the copious phantasmagorical elements in Terry Gilliam's impassioned farrago. Troubled productions are nothing new to the visionary filmmaker, but Gilliam forges ahead undaunted and gets his Fellini freak on as soon as a rickety caravan of sideshow players materializes amid the industrial ruins of modern-day London. A sort of tinsel-and-sawdust Lear, Parnassus (a marvelously grave Christopher Plummer) is a millenniums-old mystic whose shabby, horse-drawn proscenium masks a magical portal that ushers audience members into the wild alternate worlds of their imaginations. He's also a man doomed to immortality, the result of a bargain struck ages ago with one Mr. Nick (Tom Waits), a bowler-hatted Mephistopheles with unsavory plans for the doctor's bodacious teenage daughter Valentina (Lily Cole). Enter amnesic con man Tony (Ledger), who joins Parnassus's troupe and, when not fleecing giddy customers of their savings or gleaning clues about his true identity, helps the old man protect Valentina's soul.
Crammed with shifting CGI canvases and frenetic revues right out of Monty Python, Imaginarium is a galumphing bacchanal of illusionist clutter that's frequently unwieldy but rarely less than deeply felt. Much of its ungainliness derives from Gilliam scrambling to work around the void left by the untimely death of a leading player with assorted fantasy sequences in which Tony is played by guest stand-ins Johnny Depp, Colin Farrell, and Jude Law. The gimmick works surprisingly well as a whimsical manifestation of the character's gradually revealed sides, even if it ultimately neutralizes our involvement in his emotional trajectory. But there are near-sublime images swimming in the film's digital ether, from a shimmering forest of cutout trees to Daliesque compositions of Easter Island heads and chorus lines of British police officers. Best of all is Parnassus himself, who, with his Faustian deals and faith in fables before increasingly jaded audiences, emerges as not only the new incarnation of Gilliam's obsession with addled visionaries, but also as his most personal portrait of artistic endurance. Gilliam clearly identifies with the protagonist, yet his inquiry (voiced in a character's carny pitch: "Do you dream?") is less self-romancing than generously immersive, ringing throughout this haphazard, moving film as both question and invitation.