Let's begin with Andrew Hultkrans, writing for Artforum: "Based on the award-winning 2006 play Le Dieu du Carnage (God of Carnage) by French playwright and novelist Yasmina Reza, Carnage is a minor, stagey film that returns [Roman Polanski] to the physical and emotional claustrophobia of the boat in Knife in the Water (1962) and the apartment in Repulsion (1965), as well as to the misanthropic gallows humor of Cul-de-sac (1966). The narrative draws on a well-worn dramatic trope — No Exit and Edward Albee's Who's Afraid of Virginia Woolf? (1966) being just two examples; since the 1980s, they're too numerous to count — that of the small group of presumably normal adults who come together in an enclosed space and, over time, degenerate into psychological sadism and monstrous behavior…. In several respects, Carnage feels like Polanski's version of a late Woody Allen film — a modest, naturalistic production that gathers great actors, nurtures their craft, and doesn't let a lot of 'cinema' get in the way."
And that calls for an immediate jump-cut to Some Came Running: "I happened to run into a colleague who out-and-out hated it," notes Glenn Kenny. "And who said, and I quote, 'There was nothing cinematic about it.' Which I kind of couldn't believe, in the first place because more than anything else, Carnage is an absolutely virtuoso piece of cinema craft. As many of you likely know, the whole film, save for a brief prologue and epilogue, is set in a single Brooklyn apartment and its hallway. Polanski treats this space and its varied subspaces absolutely cinematically; the film is a potential masterclass in staging, blocking, camera angle, shot selection, shot length, pacing in terms of both rhythm of actual cutting and duration of shot, and so on…. It's all kind of amazing even if you're not crazy about the content of the picture. So, yes, I would say, entirely cinematic."
As Ed Gonzalez lays it out in Slant, Carnage "begins on the war zone of a playground, where a dispute between two boys leaves one with two missing teeth and a nerve in his mouth partially exposed. From there, Polanski moves us to another war zone: a warmly posh Brooklyn apartment where the parents of both boys wear at each other's 'sense of community.' Just as the implications of what happened on the playground have been parsed to the satisfaction of all parties and a door has been opened, or an elevator button has been pushed, someone insists on a provocative last word and the dispute resumes. The ego sets no one free. Almost Buñuelian by design, this satire of decivilization finds Nancy (Kate Winslet) and Alan (Christoph Waltz), parents of the 'victimizing' boy, drawn back, over and over again, to the apartment belonging to the 'victimized' boy's parents, Penelope (Jodie Foster) and Michael (John C Reilly)."
"The fun — and the movie had the house rocking with laughter at many points — comes from watching four intrepid performers rage around the set like a wrecking crew sent to knock down the Actors' Studio," writes Farran Nehme.
"Every image in Carnage is the result of a restless intelligence examining a story to find the best possible expression of each moment," writes Phil Coldiron for Fandor, "which means that Polanski, in 80 minutes and a few hundred square feet, works through what can only be the tip of a seemingly inexhaustible set of blockings and compositions — which is fitting, since the ringing phone that ends the film (save a brief coda) serves as a reminder that this could go on forever… Carnage, a film of great humor — I haven't laughed harder at an image this year than that of Waltz and Reilly toasting in a mirror behind the image of a pissy Winslet (a joke, it should be noted, that could only be achieved in cinema) — is also one of great empathy and greater insight. Polanski takes no joy in these four sad lives, but he does create a space where they might finally come to realize the state they're in."
More from Simon Abrams (House Next Door), Peter Gutierrez (Twitch), Tom Hall (Hammer to Nail), Josh Ralske (Press Play), Henry Stewart (L) and Keith Uhlich (Time Out New York). Earlier: Reviews from Venice, including Daniel Kasman's.
Updates, 10/2: Nick Schager: "Polanski's direction is as assured as ever, creating so much friction between his frame's foreground, background, and left/right/up/down quadrants that his aesthetics mirror, with pinpoint precision, the action's composed and yet immensely edgy dynamics."
For indieWIRE's Eric Kohn, Carnage "feels resolutely one-note, a fundamentally tame exercise made bearable by dialogue and performance."
And for Anthony Kaufman, "Carnage may be the most vivid depiction of our current corrosive political climate since Glenn Beck's Fox TV show."
Update, 10/3: "Polanski's biggest problem," argues Chris Wisniewski at Reverse Shot, "is his source material. Thoughtful camerawork can't get him past the superficiality of Reza's characters or the staginess of her play's central conceit."