This film was a stylistic, cultural and commercial breakthrough, the first hugely profitable Australian film in decades, and the start of the revival of the Australian film industry. The humour was utterly non-PC and outrageously crude for its day. At last the hideous ocker in England was portrayed on film in all his drunken ribald glory.
However time has not been kind to it. Some of the individual jokes are still hysterically funny, such as Spike Milligan's introduction to the hotel, the Indian aphrodisiacs, and Delamphrey's attempts at psychoanalysis. Other jokes have worn thin though having been adopted by the culture at large (e.g. the largely invented Australian slang) or use of similar jokes by other comedians. Much of the humour doesn't go beyond simply using the crude invented slang in conversation. Today it isn't particularly outrageous or funny. The purportedly stereotypical depictions of English snobbery and Australian crudity are too extreme and grotesque even for a comedy, and further detract from the effectiveness of the comedy.
Another major flaw is structural. "The Adventures of Barry Mackenzie" and its main character is based on a series of self-contained comic strips. A movie on the other hand is built around scenes of protracted dialogue, development within a scene, and development of the narrative across scenes. Indeed Humphries himself has stated he didn't believe his comic strips could be adapted for film for this very reason. As a result the film is highly episodic, with some very tendentious, unfunny and laboured links written to string the episodes together. This isn't helped by the fact that Humphries is essentially a solo performer whose stock-in-trade is the self-contained one-liner. He usually has a relatively brief setup (if any) leading to his jokes in stage performances. In consequence the dialogue is often stilted and unnatural, clumsily and unfunnily targetted towards the recitation of slang expressions or the delivery of some other self-contained comic idea. I don't normally criticise comedies for flaws in structure or logic because they are essentially vehicles for jokes, but in this case these flaws are distractingly obvious and jarring, and the jokes aren't funny enough to prevent the viewer noticing.
Still, the funniest of the jokes are classics, and overall it remains enjoyable. The sequel is funnier though, perhaps because it resolves (but only partially) some of the original's flaws.
On a historical note, the opening shot shows the Hegarty's private mini-ferry approaching the Luna Park pontoon wharf, which many Sydneysiders would fondly remember but neither of which now exist.
