Upon its release, the song received critical acclaim.
Pitchfork reviewer Ian Cohen awarded it the site's "Best New Track" designation, writing that the song "seems to be editing itself in real time with all manner of filters, manipulated vocals, swirling ambience, and a startling midsection where he mashes down the looper button and holds it. He's an expert at conveying the unexpected joy of beginner's luck behind the boards." Michelle Geslani of
Consequence of Sound similarly praised the song's second section, commenting, "The song's second half proves especially inspiring, as it features a full-on wicked, synth-y jam session and magical
vocoder harmonies."
Accolades "Let It Happen" appeared on many critics' year-end lists of the best songs of 2015.
Consequence of Sound ranked the song second-best of the year, calling it a "grand statement", "meticulously arranged", and "one of the boldest album openers of the year". The publication also said, "It's the best song [Parker's] ever written from the best album he's ever made."
Spin ranked the song seventh on the magazine's list of the year's best songs, calling it "the
Discovery of psych-rock, eight minutes of steady vamping that coalesce into an ideal synthesis of Tame Impala's gentle, kaleidoscopic powers and big-tent
EDM's ability to physically command."
The Fader ranked the song seventh-best, calling it "a jittery, stretched-out, immaculately produced sound bath that washes over the listener, beckoning them to submerge in the madness of feeling feels".
Time ranked it seventh-best as well, describing it as "mov[ing] through all the states of matter: lava-lamp keyboards give way to gaseous soundscapes, robot voices depose into fuzzy guitar riffs, and stuttering sound effects briefly make you think your speakers are having a meltdown."
Paste placed it ninth on their year-end song rankings, calling it the album's "thesis statement" and saying, "The song's multiple movements swell and bloom into the cosmic psych-rock that Tame Impala so cleverly wielded on
Innerspeaker and
Lonerism, but there's a new dimension added this time around".
Popmatters ranked it eleventh-best of the year, calling it "both the album's overture and its thematic peak" while praising it for "hit[ting] a pinnacle for a contemporary indie pop more indebted to classic disco records than
Pavement or the
Pixies".
Rolling Stone ranked "Let It Happen" at number 17 on its year-end list of the 50 best songs of 2015.
The Village Voice named "Let It Happen" the 14th-best single released in 2015 on their annual year-end critics' poll,
Pazz & Jop.
Noisey named the song the 25th-best of the year, calling it "a near eight-minute tortured wail—as defiant as it is fearful" and "a remarkable, hallucinatory exercise as comfortable in a sprawling cosmic DJ set as it is a dorm room bong sesh." At the
2015 ARIA Music Awards, "Let It Happen" was nominated for
Best Pop Release. Along with "
The Less I Know the Better", the song was one of two from Tame Impala's
Currents to reach the top five in the
Triple J Hottest 100, 2015, coming in at #5. "Let It Happen" appeared on several critics' end-of-decade lists of the best songs.
Pitchfork ranked it the 47th-best song of the 2010s, with contributor Noah Yoo commenting, "with this heavy slab of space disco, Parker decidedly broke free of any preconceived notions about his abilities".
Stereogums Pranav Trewn ranked it 35th best, describing it as Parker's way of "fashioning EDM as high art". It was ranked at the same spot on
NMEs similar list. In 2020, it was voted as the best song of the 21st century by the listeners of the Dutch radio station
NPO 3FM. ==Appearances in media==