Here's a sampling of what they had to say:
Benedict Nightingale of The London Times: "The author is Mark Ravenhill, and this time he's venturing into a future whose institional awfulness makes his [earlier play] Shopping and Fucking resemble a consumer-friendly catalogue for sex toys. Think of a collaboration between Kafka and Sarah Kane, with a bit of political Pinter and despairing Beckett added, and you've a play that sometimes leaves you feeling that a package holiday in Guantanamo Bay might be healthier than life in his new Britain. It's a none-too-subtle piece but also a none-too-usual one."
Michael Billington of The Guardian: "[Ravenhill's] new 90-minute play, although boasting a masterly performance by Ian McKellen, seems like a distillation of familiar ideas: it tells you more about what Ravenhill has been reading, rather than actually experiencing."
Charles Spencer of The Daily Telegraph: "Mark Ravenhill's new play is so up to its ears in debt to Harold Pinter that I'm not sure whether the Nobel Laureate should be merely flattered or demanding a slice of the royalties. Initially intriguing, but ultimately frustrating, the piece combines the enigma and menace of early Pinter with the political anger of late Pinter... Michael Grandage directs a tense atmospheric production, and McKellen is often riveting as the troubled Government operative, switching from urbanity to anger, and from the mundane to the lachrymose, in the blink of an eye. We are a long way here from Widow Twankey."
Quentin Letts of The Daily Mail: "Lent came a night early at the Donmar Warehouse with an evening of penitentially obscure theatre. Quite well acted but pseudishly cryptic, The Cut is a sub-Pinteresque affair. Yes, even worse than old gloomy guts! I am almost tempted to say it is worth seeing in order to behold Sir Ian McKellen. Some of his subtler gestures are beautifully done. In one scene, he and his stage wife Deborah Findlay eat supper in silence, the air filled only by the clinks of cutlery on china and Sir Ian's crisp, avian chewing. But not even his talents can rescue a work of immense self-importance."
Ruth Leon of The Daily Express: "Ravenhill is wonderfully served, not only by McKellen but also by the Donmar's director Michael Grandage, who allows not just the lines but the silences to speak for themselves. Better perhaps not to insist on precise explanations, but rather to assume that The Cut is set somewhere in the space where George Orwell starts to meet Harold Pinter. The powerful cast, Deborah Findlay as the wife and Tom Burke as the son, with Jimmy Akingbola as John, are especially impressive but it is left to McKellen to hold a loose-limbed play together."