[6] The Independent described Mutant as an album of "intricately layered sound collages" in which Arca employs mostly machine-made textures "to convey extremes of emotion – be it euphoria, menace, paranoia, melancholy.

"[7] Sam Richards of NME wrote that while Arca was clearly influenced by R&B, hip hop and dubstep, they distort and subvert these "familiar aural cues", "never allowing [their] beats to lock into conventional grooves."

[4] Simon Chandler of PopMatters said that "Mutant has Arca throwing everything — glitch, IDM, dubstep, industrial, techno, ambient, noise and world music — into an experimental microcosm of a record, an electronic hothouse where every conceivable touchstone coexists in an awkward, ugly but ultimately breathtaking harmony."

They considered this "brand of inchoate, diversified electronica to be "music for a globalized world, for an Earth in which ancient traditions sit alongside the often devastating power of new technologies".

[5] Mark Richardson of Pitchfork gave the album a very positive review, stating, "Compared to Xen, Mutant feels less composed and less indebted to classical music.