How cynical can a musical be? Director Herbert Ross and screenwriter Dennis Potter did a neat job of distilling the British TV miniseries (also written by Potter, who died last year) into the length of a U.S. feature film. Steve Martin plays Arthur Parker, an unpleasant idealist who sells sheet music (or “songs,” as he puts it) during the American Depression. When Arthur falls in love with schoolteacher Eileen (Bernadette Peters), he abandons (then returns to) his wife, who is less accommodating sexually, but does have an inheritance that Arthur wants to exploit to open a record store. In glimpses into characters’ minds, the actors dance and lip-sync with canned recordings from the era to bizarre and ironic results, as when Vernel Bagneris mouths “Pennies From Heaven” in front of a photographic blow-up of Depression-era homeless. Later, Christopher Walken (yep) puts on a show-stopping version of “Let’s Misbehave.” “I want to live in a world where the songs come true,” Arthur tells Eileen (now Lulu), in a tableaux drawn from an Edward Hopper painting. “There must be someplace where them songs are for real.” Only in your dreams.