 "Mutual Core" was described as "best" and "climactic" by Helen Brown of The Daily Telegraph, which elected Biophilia as the CD of the Week, and "literally volcanic" by Heather Phares of Allmusic. Jim Fusilli of The Wall Street Journal stated that the track is "earthbound". According to the Daily Mirror review, the track "adds angry rebuke and glitchy distorted power chordings to the shimmering, ringing percussion and natural awe that feature on the astonishing tracks" Virus "and aptly named" Crystalline "". Alexis Petridis of The Guardian praised the composition of the album and stated "There ’ s something audacious and impressive about the way" Hollow "attempts to strike a weird balance between menace and calm, the vocals as lulling as the staccato backing is unsettling. Or" Mutual Core "’ s repeated shifts from a wheezing keyboard – it was doubtless built in a laboratory by the provost of the Massachusetts Institute of Technology and professor Brian Cox, but it sounds like a 13th-century portative organ – to electronic bombardment". Möhammed Choudhery of Consequence of Sound analysed the use of Björk's voice in the album, stating:
