The initial critical reactions in London to Glengarry Glen Ross were overwhelmingly, but not unanimously, positive. Robert Cushman in the Observer called it "the best play in London." He was especially taken with Mamet's use of language and mentioned his "fantastic ear for emphasis and repetition and the interrupting of people who weren't saying anything anyway. Nobody alive writes better American." He went on to say, "Here at last, carving characters and conflicts out of language, is a play with real muscle: here, after all the pieces we have half-heartedly approved because they mention 'important' issues as if mentioning were the same as dealing with. Glengarry Glen Ross mentions nothing, but in its depiction of a driven, consciousless world it implies a great deal."

Michael Billington in the Guardian talked of Mamet's brilliant use of language to depict character and attitudes and praised both the play...