Roman Polanski adapts Yasmina Reza's dark comedy play for the screen. For better and worse, Polanski, who co-wrote the script with Reza, doesn't adapt the film very much. Outside of a dialogue free opening and closing in a park, the rest of this dialogue-heavy production takes place in one New York apartment. Primarily his top notched cast keeps the film from crumbling under its weaknesses.
Penelope and Michael Longstreet (Jodie Foster, SILENCE OF THE LAMBS & John C. Reilly, CHICAGO) have invited Nancy and Alan Cowan (Kate Winslet, THE READER & Christoph Waltz, INGLOURIOUS BASTERDS) over to their home to discuss what to do about an altercation between their two sons. The Cowans' son hit the Longstreets' son in the face with a stick. As Penelope likes to point out, their son disfigured her son. As they discuss the course of action to take tensions start to bubble up and allegiances between the foursome will shift. Carnage ensues.
The best part is Reza's attention to detail and personality. Foster plays Penelope as a woman who frets a great deal about the problems of the world. Liberal guilt would be her primary motivator. She is determined to make sure the Cowans understand how much of a "big deal" this fight was. The Cowans seem like they just want to get back to work. Waltz plays Alan as a workaholic lawyer who is far more interested in his client with a PR problem than what his son did. He doesn't like being lectured by Penelope and has fairly resigned himself to the fact that his son is an animal. His ambivalence only agitates Penelope more.
Winslet's Nancy puts forth the effort to at least appear concerned, but is increasingly embarrassed by her husband's constant cellphone conversations. Reilly's Michael tries to keep the peace and doesn't want to take anyone's side. It's his method of resolving this problem as fast as possible, so he can move on and forget about it. But their conciliatory attitudes change after a few cups of coffee and a glass or two of booze.
Part of the issue I had with the script (could even be the play, but I have not seen it) was that it uses one contrivance after another to keep the Cowans at the Longstreets' apartment. The problem's answer stares you in the face, because the characters discuss bringing the kids together to work out the problem together. If this happened, the two couples would have a reason to sit and talk to each other. Alan, especially, seems like he would have left long before the point that he's cleaning vomit off his pants in the bathroom.
Once CARNAGE gets past some of its initial contrivances of forcing the characters to stay together, the plot finds reasonably awkward motivations for the Cowans to stay and the awkwardness opens up the gates for the conversation to turn toward the vicious. The story doesn't have any grand message about human nature other than civilized interaction between people is a fraud. In the end, the film works as a detailed character study where Penelope's "heart on your sleeve" philosophy seems to get crushed by the powers of the god of carnage.