The record is split into four extended pieces, each about 15 minutes in length. Over the course of the LP, languorous rhythms grow into jungly thickets of sounds. These instrumentals are among the richest Shackleton has ever made. Full of mossy-textured synths, dizzying drums and all kinds of whirring atmospheric sounds, the album, though less dense than usual, is an enveloping experience.
Behind The Glass's spacious arrangements leave plenty room for Anika, who—considering Ernesto Tomasini's operatic stylings and Vengeance Tenfold's terse spoken word—is the most conventional singer with whom Shackleton has worked. The album's narrative is both love story and tragedy, but Anika's careful enunciations, as a foreground for Shackleton's mystical music, can feel awkward and affected.
When Anika and Shackleton hit their groove, the results are dazzling. The album's chaotic fourth passage is particularly exciting. Shackleton's arrangements shake and crumble around Anika, who, as the drums grow more intense, sings: "Don't look at my reflection / Reality has not been kind." Had the album been this considered and symbiotic throughout, Behind The Glass may have ranked among Shackleton's best work.
Much of his catalogue has touched on religion and spirituality, themes that fit his mysterious tribal music, but the comparatively modest scope of Anika's presence seems at odds with Shackleton's swirling synths and expansive arrangements. His recent vocal records—Devotional Songs with Ernesto Tomasini and the expansive, Coil-esque Sferic Ghost Transmits with Vengeance Tenfold—felt like epics tailored to their subject matter. Behind The Glass is a melodrama whose earthly emotions distract from the otherworldliness Shackleton's music evokes.