Following their enticing, percussion-less, synth-laden score for 2014's Ex Machina, composers Ben Salisbury and Geoff Barrow deliver their second score, this time for Alex Garland's Annihilation, a sci-fi psychological thriller that explores the themes of identity and biology. The effort is a sure-fire sonic departure from the sound that ran throughout their former effort: Whereas Ex Machina was made up of pulsating, arpeggiated synths and fuzzy basslines that filtered and weaved in and out of the mix, Annihilation approaches tension and mood in an altogether different way. The first half of the score consists of heavily reverberated percussion, ethereal soundscapes, and arpeggiated acoustic guitar that juxtapose threat and intrigue equally. Tracks such as "What Do You Know?" and "Approaching the Shimmer" do this wonderfully, focusing purely on atmosphere rather than structure. As the album progresses, forlorn strings adorn each piece, such as on "Plant People" -- an eerie piece composed of discordant bass, foreboding cello, tinkling wind chimes, and the occasional sweltering sound effect that recalls some of the noise involved in late composer Jóhann Jóhannsson's final score for Denis Villeneuve's Arrival in 2016. The final third of the album segues into more threatening and mysterious territory -- "Lighthouse Chamber" delivers a kind of nauseating, swirling ambience before the 12-minute-long "The Alien" begins. The latter is a highlight of the album, bringing together many of the aforementioned elements into one cohesive composition; wonderfully rich strings rise to a crescendo before suddenly, out of nowhere, fuzzy synth leads break through, giving way to ghostly ambience and unexpected stabs of electronica that build to a tumultuous end. The score for Annihilation is a refreshing listen for soundtrack aficionados and proves that Salisbury and Barrow have plenty of tricks up their sleeves as innovative composers.