Hi, Mom! is, regrettably, an almost total waste of time. The filmmakers have run out of ideas: they either try to milk the same situations as [in Greetings] (making Peeping-Tom sex films), or if they come up with something new (militant Black Theater that humiliates and manhandles white liberal audiences), they stretch it out as desperately as beggars their last crust of bread.
There are even more basic problems. Hi, Mom! is clearly improvisatory cinema, an enterprise that requires true brilliance somewhere. It may be in the director (e.g., Fellini, in some of his earlier films), or it may be in the performers…. Here, however, brilliance is not forthcoming…. And whereas Greetings had a unifying plot device—how to stay out of the Army—there is not such central motif here…. I could go on, but let me leave a stone or two unturned, in case you do want to see the film for the sake of your fond recollections of its predecessor. It needs to keep its few mild surprises undivulged. (p. 124)
John Simon. "The Youth Film: 'Hi, Mom!'; 'The Magic Garden of Stanley Sweetheart'" (originally published as "Youth Films: Onward and Downward," in The New Leader, Vol. LIII, No. 11, May 25, 1970), in his Movies into Film: Film Criticism 1967–1970 (copyright © 1971 by John Simon; reprinted with permission of The Dial Press), Dial, 1971, 124-26.∗