Adapting a play from stage to screen can flummox the best filmmakers. Many otherwise brilliant directors -- who train themselves to always think visually -- fail to realize that theatre is still essentially a verbal medium, where the words the actors speak are supposed to take precedence over how good the mouth looks that is speaking them.

Roman Polanski did not make that mistake in adapting Yasmina Reza's comedy God of Carnage, wisely letting four great actors act and concentrating instead on creative but unobtrusive camera work to make a small Brooklyn apartment as expansive as a mansion.

(Title slightly amended, Carnage was actually filmed in Paris because of a pending arrest threat by U.S. authorities on decades-old sexual assault charges; Polanski collaborated with Reza on the screenplay while under house arrest in Switzerland.)

Two couples -- Allen/Nancy (Christoph Waltz and Kate Winslet) and Michael/Penelope (John C. Reilly and Jodie Foster) -- meet at the apartment to discuss an unfortunate playground incident in which Allen and Nancy's 11-year-old son struck Michael and Penelope's son in the mouth with a stick.

The afternoon goes increasingly awry as the initially self-effacing Michael and Penelope become more and more resentful of both the incident and Allen and Nancy's corporatist pretentions -- Allen is a Big Pharma lawyer who stays glued to his precious smartphone discussing a lawsuit over a possibly faulty drug.

Allen and Nancy, meanwhile, display predatory instincts of their own which seem to mirror those of their "maniac" of a son, a parallel which Allen himself cements with the Darwinistic, title-providing line, "I believe in the god of carnage."

While Waltz and Winslet have the easiest characters with which to get a laugh -- Waltz's nearly deadpan Teutonic delivery is perfectly suited to the wolf-like Allen, while Winslet's character has stomach nerves which result in a fairly graphic projectile vomiting that's essential to the plot -- the most valuable work is done by Foster and Reilly.

Occasionally Foster overplays the tightly-wound, easily wounded nature of Penelope -- I have never seen so many prominent veins in anyone's neck -- but Reilly absolutely nails the transition of Michael from well-meaning, smiling schlub who sells home furnishings to self-professed "short-tempered son of a bitch" who, in the end, is a more authentic alpha male than Allen.

I cannot say enough about his performance; if Reilly doesn't make this transition believable, the entire film basically fails. At every point in every way, whether in inflection or volume or timing, he makes the right decision.

Winslet, again displaying her solid, 95 percent accurate American accent, responds to the skill of her fellow actors and dials back some of her more stagey mannerisms in a delightful performance.

My only complaint -- and it's a small one I've seen in other plays adapted to screen -- is that the film's dialogue continues right after each obvious laugh line. Onstage, actors know when to "hold" for laughs that are likely to come, but this doesn't happen in Polanski's Carnage.

I know cinema's different -- as I'm reminded constantly by film mavens -- but Reza's sardonic rhythms are meant to be heard regardless of the medium, and a few momentary pauses wouldn't have hurt the pace of the film at all.