Contemporary reviews of The Glow Pt. 2 upon release were generally positive. Matt LeMay of Pitchfork called the album an "alive" and "sprawling, swirling composition", while stating that "parts of The Glow Pt. 2 are absolutely breathtaking" due to its stereoscopic enhancements. LeMay felt that the album "exceeds even its predecessor in capturing the simultaneous wrath and fragility of nature" and praised the title track as being "the single most breathtaking song on the album". Dave Heaton of PopMatters described The Microphones' approach to music as "free and idiosyncratic" and "constrained by few boundaries, a fact that allows them to travel through various unique musical lands". Writing in Under the Radar, Wendy Lynch stated that The Glow Pt. 2 "encapsulates chaos with sparatic [sic] changes and bullets of sound" and labelled The Microphones as "one of the most original, interesting bands to come out in the last 3 years".Stylus Magazine's Tyler Martin asserted that The Microphones "spew innovation every second of this disc" and that the album "promises something you have never heard before and delivers it, perhaps more than you’d expect". Heather Phares of AllMusic stated that "it's The Glow, Pt. 2's deep, nearly spiritual yearning that makes it the Microphones' most compelling album to date."
Retrospective reviews of The Glow Pt. 2 have expressed more general critical acclaim for the album. In a review of the album's 2008 re-issue, Brian Howe of Pitchfork stated that The Glow Pt. 2 remained to be Phil Elverum's "crowning achievement" and that "seven years of imitation have done nothing to dull its impact-- it sounds as unaccountably grand now as it did in 2001". Brock Thiessen of Exclaim! described the album as "a brave new world where solar noise bursts over sprawling epics of the most intimate nature" and stated that "it's clear age hasn't tainted the kaleidoscopic Glow Pt. 2 in the least". Both reviews praised the bonus material on Other Songs & Destroyed Versions as essential, with the latter asserting that while "none of the new lyrics clarify the overarching story", the new tracks "reveal a few more glimpses of a distant, haunting world that's all the more alluring for its incompleteness". Writing for PopMatters, Dan Raper stated that "Microphones fans will find Other Songs & Destroyed Versions more than worth the investment".
After a second reissue of The Glow Pt. 2 in 2013, Colin Joyce of Consequence of Sound hailed the record as "a masterwork of sequencing as it bleeds and blends from track to track". Dan Hancox, writing for The Guardian in its "Hidden treasures" column, described the album as "a masterstroke" and "a millennial Daydream Nation".The Line of Best Fit lauded The Glow Pt. 2 as an "essential work of modern indie", while Stereogum's retrospective feature on the album stated that the album's "bond with listeners, as individuals," surpasses its critical success.