Feel Flows is the band's first major archival release since Wake the World and I Can Hear Music in 2018, and the first issued on physical media since Sunshine Tomorrow in 2017.

Criticism was reserved for the poor mastering quality, particularly with respect to the presence of digital artifacts, excessive treble, and extreme dynamic range compression.

[2] Disc five includes several tracks drawn from Dennis Wilson's aborted solo album, Poops/Hubba Hubba, that he wrote with Beach Boys touring musician Daryl Dragon.

[5] Studio recordings that had not seen release in any form include "'Til I Die" (piano demo), "Big Sur" (1970 version), "Sweet and Bitter", "My Solution", "Seasons in the Sun", "Baby Baby", "Awake", "It's a New Day", "Medley: All of My Love / Ecology", "Before", "Behold the Night", "Old Movie (Cuddle Up)", "Hawaiian Dream", "I've Got a Friend", "You Never Give Me Your Money", and "Won't You Tell Me" (demo).

[6] In December 2019, as part of their annual copyright extension releases, Capitol and UMG issued 1969: I'm Going Your Way, an EP that consisted of three unreleased tracks drawn from the Sunflower sessions: "I'm Going Your Way", "Slip On Through" (an alternate version), and "Carnival (Over the Waves)".

"[9] According to reporter Joel Goldenberg, many fans speculated that Mike Love was responsible for stalling the compilation, and petitions that called for its release were posted online.

[10] In November 2020, a Beach Boys entry titled 1970 Release was uploaded to AllMusic's website containing 64 30-second samples of unreleased material and alternate mixes from the band's 1969 to 1970 period.

Hughes highlighted the live tracks and Dennis' unreleased songs, concluding that "Feel Flows is emphatic proof that The Beach Boys never stopped making sublime, artful, spiritually invested music, no matter how far they'd fallen in popular opinion.

"[5] Reviewing the box set for Ultimate Classic Rock, Michael Gallucci decreed that Sunflower and Surf's Up were among the band's best albums and that there "aren't too many rough patches" spread across the bonus tracks.

"Nothing here will attract listeners who think the Beach Boys faded into irrelevance after the mid-'60s, but fans will discover plenty of exceptional and unheard tracks from one of their most fertile and productive runs.

"[25] AllMusic reviewer Fred Thomas felt, "Most casual listeners will be daunted by the depths to which the massive set travels, but it's must-hear material for the committed and the fascinated.