Arktau Eos proudly proclaims that _Mirrorion_ is devoid of electric instruments, which would be an empty statement if uttered by, say, a black metal band, but of greater import when uttered by a dark ambient act. In lieu of electric instruments, "the natural, inherent vibrations of wood, bone and metal" are used, a description which includes the predictable and the orthodox such as an acoustic guitar as well as other, more unconventional and disturbing instruments such as kanglings (Tibetan trumpets made from human thighbones), accelerating steel-plate rolls, and singing bowls, which collectively weave a minimalist sonic tapestry. There is a strong magicko-spiritual aspect, not only suggested by the cyclopic cover sigil, but also by their own interior proclamations and song titles, which suggest a Thelemic influence; magic influence or not, strong ritual atmosphere is sustained throughout the album's lengthy playing time.

With seventeen tracks at just over an hour, this certainly is an ambitious release; however, while it may be obvious that it will not appeal to everyone, even dark ambient fans may struggle to appreciate its beauty, as drones, which provide the underlying structure for much of the genre's work, are noticeably absent. Nonetheless, it remains a stunning example of the genre.