Just who makes those animated films that people flock to, with or without children, in order to recapture their childhoods? According to Shawn Nacol’s witty and tart Rough Sketch, they’re generally people you would never consider leaving your kids with.

The awkward and focused Barbara (Tina Benko) is appalled that none of the furry little cartoon animals have an anus; the goofy and amiable Dex (Matthew Lawler) just wants to forget how talented he is and focus on hiding Easter eggs in the background for dedicated geek viewers. But working side-by-side in the office over Christmas on a much delayed, way over-budget movie about anthropomorphic coffee beans getting “in and out of hot water,” Barbara and Dex revert to snarling primitives that their movies sanitize into helpful critters.

Like the nihilism that Barbara is intent on injecting into the movie, the play sneaks up on you. What seems like a frothy and charming romp in the first act turns both darker and funnier in the second. The performances also morph into something deeper than their original shallowness. For most of the play’s first act, Benko seems to be giving nothing more than a stellar Bebe Neuwirth impression. Staring at Dex with a deadpan face and wide eyes, Benko’s Barbara is the epitome of awkward charm. “You smell a little like raw meat and starch,” she says in a guttural voice by way of flirtation.

But the genius of casting Benko is that despite Barb’s slowly revealed, outrageously dark worldview, Benko manages to make every statement ring true. When she tells Dex, “The world is bad, but not as bad as the lies we tell about the world are worse,” the audience at the performance I attended murmured to itself in stunned agreement. And Dex, for all of his easygoing charm, shows a streak of stubborn optimism that belies his general apathy. He might claim that the films are just a chance for him to doodle away his days, but he genuinely cares that the kids in the audience will leave just a little bit happier. He sees Walt Disney as the benign patriarch, indulging the children-audiences of the world; Barbara sees him as a dictator who has forced the world to remain slaves to the idea of happy-ever-after (one of the play’s best exchanges has Barbara rattling off the real endings to evergreen Disney films).

The one misstep in this first rate production (which includes a slavishly detailed set from Peter R. Feuchtwanger) is director Ian Morgan’s choice to stage chunks of the play with the actors on the floor. In a larger space, that wouldn’t be a problem, but in the blackbox 59E59 Theater, the actors are hidden from view if you’re not in the first row.

But Nacol’s script is strong enough to work, even when his characters are invisible. Rough Sketch is about more than the merits of happy endings in films; Nacol has accomplished what the best movies do, cartoons or not: He’s making the audience examine their own worldviews. So… Team Barbara or Team Dex?

Through Jan. 31, 59E59 Theaters, 59 E. 59th St. (betw. Park & Madison Aves.), 212-279-4200; $18.