"[17] Will Richards of NME commented that while Gonzalez may have shunned commercialism, his songs "remain sugary, dreamlike and entirely welcoming", describing the album as a "huge, fizzing world of sound that's designed to feel as awe-inspiring as possible".

[12] Heather Phares of AllMusic opined that the album "capture[s] what makes [Gonzalez's] music tick: an unabashed, maximalist love of spinning dreams" whose "reveries reveal he hasn't lost any of his talent for crafting massive sound worlds".

[13] Kate Crudgington of The Line of Best Fit stated that while a "sweet escape from the overwhelming world that inspired it", Fantasy is "one that listeners will drift in and out of, but it retains the exhilarating signature sound" the band are known for.

[11] Fred Barrett, writing for Slant Magazine, found that M83's sound "has lost some of its novelty" and noted "something that's conspicuously absent here are the instantly gratifying pop hooks of past M83 tracks like 2008's 'Kim & Jessie'", with Gonzalez now letting the lengthier songs "slowly unravel".

[10] Sputnikmusic staff writer YoYoMancuso concluded that Gonzalez "unfortunately continues to struggle with cohesion and distilling his musical ideas down to their most valuable elements, but his latest full-length is an undeniable improvement over his mid-late 2010s output".