Apologia, Bush, London<br>Everything Must Go, Soho, London<br>Oklahoma! Festival Theatre, Chichester

Alexi Kaye Campbell triumphs as his sharp new play &ndash; both satirical and emotionally crucifying &ndash; exposes tensions between principle and parenting

So what, exactly, is an apologia? "It means a formal, written defence of one's opinions or conduct ... Not to be confused with an apology." Thus Paola Dionisotti's Kristin – renowned art historian, veteran left-wing activist and lousy mother – defines the title of her autobiography and also of Alexi Kaye Campbell's drama in which she, Kristin, is confronted by Simon and Peter, her neglected sons.

Campbell won a Critics' Circle Award for his first play, The Pride, and Apologia, his second, doesn't disappoint, staged by Josie Rourke with fine, closely observed acting. The scenario may not be dazzlingly original: a reunion and supper party turning sour. However, no apology is needed on Campbell's part. This is a sharp, satirical and poignant drama.

Rourke's production is intimate. Seated at the pine table in Kristin's boho kitchen, Tom Beard's Peter simmers with rage while the sardonic Dionisotti takes swipes at his career in banking; at his born-again fiancée Trudi (Sarah Goldberg); and at Simon's designer-label soap-star girlfriend, Claire (Nina Sosanya). Philip Voss is also splendid as Hugh, Kristin's witty, camp old crony.

Dionisotti struggles with Kristin's prolix lecture on Giotto, and milks her last scene somewhat with a silent scream. In between, however, her tête-à-tête with John Light's fragile Simon is emotionally crucifying. With echoes of The Seagull, he sits quivering with grief, as she picks splintered glass out of his palm but can't stop conversationally needling him.

Campbell's play also tackles bigger sociological issues. It assesses the gulf between the generations, weighing up the vintage values of the Sixties and Seventies. This is Kristin's night of reckoning, firstly as a supposedly liberal yet snobbish intellectual, and secondly as a feminist who put her career and political crusades above parenting. A thought-provoking drama, with surprise twists in its sympathies.

Meanwhile, Soho Theatre's artistic director, Lisa Goldman, has invited 10 writers to respond, pronto, to the credit crunch. Everything Must Go is a clutch of vignettes, staged bargain-basement style, with just a fortnight for rehearsals, and packing crates for a set.

The result is the artistic equivalent of boom and bust: some excruciating lows but also several dramatic highs. Anaphylactic is a deliriously awful verse play about hire purchase, eating bees, and orgasm. The City ditty contributed by Steve "Roaring Trade" Thompson is disappointingly feeble too. No matter, though. The grim forebodings of poverty-stricken xenophobia, penned by Kay Adshead and newcomer Ron McCants, are quietly chilling. Marisa Carnesky's burlesque magic act is droll, turning her mortgaged-to-the-hilt home into a sword box. And the picket-line play, Six Minutes, inspiringly voices the righteous anger of the underdogs, protesting at fat-cat pay-offs. This is by Paula B Stanic: another name to watch.

In Rodgers and Hammerstein's Oklahoma!, the cowboy Curly hawks his possessions to win his sweetheart, Laurey. He risks trading in his pistol to outbid his sinister rival, Jud, who is determined to procure Laurey's hamper at the farmgirls' harvest auction. To say that Jud is after her pumpkin pie would be putting it politely.

The low-budget design is the most pleasing aspect of this Chichester Festival production, directed by John Doyle (of Sweeney Todd renown). David Farley has created a beautiful set by rubbing two pennies together imaginatively. Panoramic skies are evoked by sheets slung over washing lines, their long creases looking like cirrus clouds. And the sloping stage is a patchwork of old planks, like a bird's-eye view of ploughed fields.

The letdown is that Michael Xavier's Curly and Leila Benn Harris's rather nasal Laurey lack sexual chemistry. He's mellifluous but slightly wooden – kinda tall, dull and handsome – and you'd be forgiven for thinking that she really ain't interested. Of course, she's meant to be playing hard to get, not wanting to look completely smitten. But surely their teasing duet "People Will Say We're in Love" should be accompanied by hints of irresistible attraction as she sings, "Don't sigh and gaze at me. Your sighs are so like mine." Instead, Benn Harris prefers to stare out over the audience and, if possible, stay a furlong from her beau.

The secondary love triangle – in the comic subplot – is more winning. Michael Matus gets away with playing the cheeky pedlar Ali Hakim as a blacked-up fraudster, peeling off his exotic moustache and slipping into an all-America drawl when alone. As the blithely wanton Ado Annie, Natalie Casey offers an enjoyably coarse caricature, even if we see her splayed bloomers once too often. And Michael Rouse is positively gymnastic as her other suitor, punctuating every line with handsprings, and spinning Casey like a Catherine wheel (choreography by Nikki Woollaston).

That said, their perkiness becomes tiresome, and what grittiness there is doesn't feel authentic. Craig Els's Jud may glower, yet this show is syrupy at its core. The entire cast chorusing "Aye-yip-aye-yo-ee-ay! ... Oklahoma, OK!" should, I guess, have left me on an ecstatic high – only I felt as if I'd been sucking on candy all night, and my soul was rotting.

'Apologia' (020-8743 5050) to 18 Jul; 'Everything Must Go' (020-7478 0100) to 4 Jul; 'Oklahoma!' (01243-781312) to 29 Aug