The concept of aliens whose only difference is that they have bald cone-shaped heads is a single joke but surprisingly proves to be something that is an amazingly fertile one for the film. Most of the time the humour derives from appealingly silly variations on human behaviour – the Coneheads sleeping in upright beds replete with bedside lamps or wearing conical motorbike helmets – and/or they giving familiar terms polysyllabic names – “a costume designed for adolescent mating rituals” (frilly prom tux) or inviting the neighbours over to “char some animal flesh” (on the barbecue). Coneheads holds an affably appealing self-view of America as a poly-cultural melting pot – one where even aliens are able to slot in and live as a normal American middle-class family with no-one finding their oddities even the slightest out of the ordinary, not even really the US Immigration official nemesis whose only real problem is that he just wants to get them registered. Both Dan Aykroyd and Jane Curtin appear wonderfully attuned in their clipped monotonic intonations and polysyllabic terminology and give rather good deadpan performances.

Where Coneheads starts to falter is during the Remulak scenes where it tries to move beyond the single-note joke and ends up beached. The script, which is basically a series of satiric skits, doesn’t really lend itself to drama – the US Immigration nemesis subplot barely does, but when the film is blown up into a razzmatazz drama with A-budget effects and a climax involving Dan Aykroyd taking on a stop-motion animated monster, it gets too far beyond the slimness of the original concept. Certainly the effects sequences are top-notch, but in trying to make itself more than it is, Coneheads overreaches itself. But when it stays with all the visual gags, the film is appealingly congenial. Considering the peculiar sense of humour the film has, it is no real surprise that Coneheads was a financial flop.

Steve Barron is a director of some genre association. He also made the computer romance Electric Dreams (1984), Teenage Mutant Ninja Turtles (1990), The Adventures of Pinocchio (1996) and Rat (2000) about a man who turns into a rat, as well as the Hallmark tv mini-series’ Merlin (1998), Arabian Nights (2000) and Dreamkeeper (2003). Barron also founded Canada’s Mainframe Entertainment, the world’s first commercially producing computer animation company and the producers of tv series such as Reboot (1994-2001) and Beast Wars: Transformers (1996-9).