Stephen Earnest’s review published on Letterboxd:
O.C. and Stiggs is like the retarded step-brother of Fear and Loathing in Las Vegas inasmuch as it deals with two reckless and dimwitted loafers who derive enjoyment from tooling the main drag in search of something to destroy - except they're not hammered 24/7. Their quest: exacting glorious, catastrophic revenge on the American middle class, which is epitomized by the Schwab family.
Ironically, O.C. and Stiggs suffers from the same problem that Fear and Loathing does: length. It starts off on a good foot and continues that way for a solid hour, keeping the gags and their accompanying laughter coming, but then, after the titular characters arrive back home from a trip to Mexico, the story sort of peters out into a mess of Apocalypse Now references and jokes that feel almost nonexistent, and that's when you start to feel the length, which reveals itself in one of my more hated things a person can do while watching a movie: clock-watching. (I'll admit even I felt myself do the dirty deed.) There's never really any plot-building throughout the damn thing, which isn't a problem - at least, not by my standards - but it would've been nice if Altman had let us in on what really in the hell is happening during that final half hour.
Still, it's quotable to the umpteenth degree ("If we could combine really loud noise with the ugliness of poverty, we'd have the ideal car") and way more enjoyable than people make it out to be, and even if it isn't great Altman, it's still Altman, and that's something you relish every chance you're given.