David Harrower’s haunting Knives in Hens at Donmar Warehouse, which lasts 90 minutes and is acted without interval, is strictly for serious theatregoers who are prepared to make an effort. There are just three characters, all medieval peasants: an ignorant ploughman, his superstitious wife and a widowed miller, who can read and write. The language they speak, stripped right back, is spare, poetic, archaic and muscular. The trio seem to be taking part in an earthy and violent ritual, re-enacting some ancient myth, a timeless fable of lust and murder. Yaël Farber’s production, excellently acted by Christian Cooke, Judith Roddy and Matt Ryan, is notable for its physicality and rawness. Soutra Gilmour’s setting, powerfully lit by Tim Lutkin, is noteworthy for its darkness and starkness. The large grey rolling millstone could be some primal idol. Luke, an aerospace billionaire in American playwright Christopher Shinn’s Against at Almeida Theatre, gets a message from God to “Go where there’s violence.” Ben Whishaw’s intelligent, articulate and immensely likeable performance holds the audience’s attention during Ian Rickson’s 2 hour and 50 minute-long production. Luke’s messianic mission takes him to a school, university, prison and factory. He wants to change the way people think. The more Christ-like he becomes the bigger the cult. It is not difficult to guess how Shinn’s play will end. More than a quarter of adolescents and teenagers have been bullied repeatedly either through their mobile phones or on the internet. Canadian playwright Jordan Tannahill wrote Late Company, his involving 75-minute social drama, in 2011 when he was only 23. It’s about grief and how people handle it in different ways. It is also about the difficulties of being a parent today. A 16-year-old boy commits suicide as a result of cyber-bullying. The boy’s parents decide to invite one of the bullies and his parents to dinner in the hope of some sort of closure. Many people would think such a meeting most unwise and have very strong reservations about its healing efficacy without professional support. The cast at Trafalgar Studios – Lucy Robinson, Todd Boyce, Alex Lowe, Lisa Stevenson and David Leopold – is first rate and the confrontations, directed by Michael Yale, have real dramatic force. Joe Orton, variously described as the Oscar Wilde of welfare state gentility, the Douanier Rousseau of the criminal suburbs and the Grandma Moses of the rubbish dump, was no respecter of the Catholic Church, the police or indeed the dead. Loot, which premiered in 1965, is an outrageous mixture of black farce, violence, sex and bad taste. Comic absurdity and sheer nastiness are fused with style and wit. It’s given a raucous revival by Michael Fentiman at Park Theatre, Finsbury. John Galsworthy, once a major playwright famous for his social criticism but now rarely performed, described Windows as “a comedy for idealists and others”. Premiered in 1922, it is not one of his best plays and the actors at Finborough Theatre struggle to make it work. Julian Slade and Dorothy Reynolds’s Salad Days, a musical about a magic piano that can make people dance, is revived at Union Theatre. It ran for an amazing 2,288 performances in the 1950s. It’s so silly, so twee, so whimsical and so frightfully English; it’s best left to amateurs to perform.