The songs on "Closer" were drawn from two distinct periods. The earlier guitar-driven compositions were written during the latter half of 1979: "Atrocity Exhibition", "Passover", "Colony", "A Means to an End" and "Twenty Four Hours". All were played live during that year, with some being recorded for various radio sessions. The album's other songs were written in early 1980, and included more prominent use of synthesisers: "Isolation", "Heart and Soul", "The Eternal" and "Decades". Most songs were written or structured during jam sessions in the band's practice room.