Writing for Pitchfork, Zoe Camp described Magma as "their most accessible release yet, melodically immediate and charged with emotion." Camp sided with Epstein and other critics in considering the album a stylistic departure from previous releases. Camp wrote that on Magma, Gojira "deliver a taut, catchy crossover effort that inoculates their [heavy] metal with equal parts melodic immediacy and emotional intimacy, while retaining the pillars of their caustic panoply: mathy riffs, uncommon time signatures, ferocious, death-metal-styled vocals, and above all, overpowering anxiety. The new sound's largely a consequence of the Duplantiers' grief; their mother died during the album's gestation, forcing the brothers to get out of their own heads and revisit the material they had so far—often fighting back tears during the sessions."
