Abandoning his middle period flirtations with jazz improvisation and contemporary orchestration, [on Joe's Garage (Act I and Acts II & III)] Zappa has reverted to the conceptual doo-wop format he last employed on the Mothers' Kafkaesque exercise in cosmic paranoia We're Only In It For The Money. Joe's Garage is similarly premised on the imminent prohibition of music … as it traces the journey of protagonist/guitarist Joe through the travails of the robot age…. [The] greater portion of this extravaganza is of no more substance than hamburger helper…. [Frank's] purulent invective oftener-than-not degenerates into the most putrid scatological doggerel, lacking, however, the power to shock that his comparatively tame satire originally had. Between occasional thrusts of barbed humor and even rarer bursts of creative music, Zappa bogs down in a bilious quagmire of obscenity, misogyny and self-pity, raging with equal incomprehension over the demise of psychedelia and the recent emergence of the new wave. From enfant terrible he has become the old pooperoo, a cynical guru whose teenybopper minions are unlikely to be daunted by his latest cautionary fable on the pitfalls of a musical career. (p. 48)
[His] current magnum opus is a vulgar bore. Perhaps a stage mounting might distract audiences from the humdrum music, but the recording alone is not sufficient to sustain the attention of any non-PCP user over the age of 16, which is of no moment to the bulk of Zappa's following anyway. (p. 50)
Larry Birnbaum, "Record Reviews: 'Joe's Garage'," in down beat (copyright 1980; reprinted with permission of down beat), Vol. 47, No. 4, April, 1980, pp. 48, 50.