Dear Ceri,

So, you're faced with the near-impossible task of bringing a Pulitzer-Prize winning play to the screen and making it feel like something more than just a sequence of transplanted scenes. The first (and perhaps most essential) challenge is to find a frictionless way to expand the story from the confines of the stage without resorting to gimmickry or novelty. The original staging of August: Osage County by Chicago's Steppenwolf Theater featured multiple rooms of a vast farmhouse, each illuminated and darkened as characters moved from place to place. To give himself a little room to breathe in his film adaptation, director John Wells does the usual things: transposes conversations to other locations, lingers on big, beautiful shots of bruise-colored prairie cloudscapes and tall grass moving in waves, and throws in a few appended scenes (that the screenplay is written by the play's author, Tracy Letts, makes these interstitial feel a little criminal).

But the success of August: Osage County is less about scope than it is about richness--and that's the second big challenge in bringing theater to the movies: how do you show the richness of the world in a manner that befits the particular strengths of cinema? And how do you do it without losing the value inherent in the original piece of art? In a way, its not that different from adapting a comic book, or video game, or board game, or breakfast cereal, etc. You find what is elemental in the source material, and you exploit it in new ways.

So, what is elemental in August: Osage County?

You might argue that it's Letts' script. It's all the southern gothic stuff of Tennessee Williams (with a dash of Eugene O'Neill's domestic strife): a patriarch goes missing and draws back to the homestead three daughters and their respective families to do battle with the widow: a venom-spitting harpy, fuelled by pills and self-pity who seems dedicated not to reconciliation but to its opposite. She's larger-than-life and pathetic, devoted to her family and unspeakably cruel to them. "I'm just truth-telling," she says at one point. "And some people are antagonized by the truth."

But it makes about as much sense to follow the script of a play word-for-word as it does for a comic book movie to be built verbatim from the dialogue in word balloons. So you might argue, instead, that the performances are that elemental thing. After all, superlatives can no longer account for Meryl Streep's impossible-to-fathom talent, and Julia Roberts somehow manages to keep pace - and in some scenes exceed! - Streep's self-destructive radiance. But the performances alone, as wonderful as they are, don't account for how well the story plays out in the world of film.

In a stage play, actors have nowhere to go; the sense of claustrophobia is what lends the medium so well to domestic dramas. The one thing theater can't modulate with the same effectiveness as movies is ambience. And it just so happens that ambience - the mood and atmosphere and ecology of this old farmhouse and the surrounding Great Plains - is the essential element of Tracy Letts' play.

And that, Ceri, is where I think you contributed to making August: Osage County the best film of 2013.

When Julia Roberts (the eldest daughter) and her family first arrive at the Oklahoma farmhouse, they complain about the heat, and beneath their voices we hear the electric hum and tick of insects, the whisper of far-off cars, and the dull drone of wind (even the wind sounds hot). Later, during, one of the most uncomfortable (and uncomfortably comical) family dinners ever filmed, the quiet chiming of cutlery scores the increasingly vitriolic back-and-forth--and when the sound of it disappears altogether, we don't need a wide shot to see that everyone has stopped eating.

When Streep, delirious from painkillers, dances to Eric Clapton's "Lay Down Sally", the absurdity of her wild movements is subverted when the song slowly drops from the soundtrack, and, in the same way that laughing and crying are often indistinguishable, we suddenly can't tell if she's celebrating or grieving.

The sound design is perfect, and so is the mix. A story like this, which relies so heavily on machine gun exchanges of dialogue - and, just as vitally, on the beats of stunned silence between - is all about tempo, and the care that was put into the way the voices, music, sound beds, and foley effects work together is indicative a movie that aspired to be something more than merely a filmed play. Despite its lofty, prize-winning origins (and the expectations that come with it), August: Osage County is, through and through, a motion picture, and there wasn't a better one released this year.