You can’t laugh for 100 minutes straight. Hence the hermetic perfection of the half-hour sitcom. Hence the humour droughts midway through loads of comedies. Hence the stop-start, sketch-show format pioneered by the Pythons.
Plonking us into prehistory like a less-imaginative Lynx ad, this Judd Apatow- Harold Ramis (Mc)love-in begins as genial Flintstones-y fun.
Zed (Jack Black) and Oh (Michael Cera) are tribesmen shunned for their less-than-satisfactory hunter-gathering skills – a comic scenario as ripe as the forbidden fruit on the Tree Of Knowledge.
But when Zed snaffles one of the aforementioned apples, the pair are banished from this brave, barely explored new world into a Biblical era plundered to death in The Life Of Brian.
Whereas Brian had the greatest story (n)ever told to satirise, this is just pick’n’mix puerility. En route to Sodom (“Best thing about Sodom? The sodomy.”), our heroes encounter a series of Old Testament types, some nifty (Hank Azaria as a foreskin-obsessed Abraham), some naff (Oliver Platt channelling Uncle Monty as a camp priest).
It’s amiable enough, like an anally fixated Asterix adventure, but the material’s thinner than the Turin Shroud, and the quality plummets whenever Cera’s offscreen or Platt’s on it. Surely the last thing anyone needs is another inadequately attired fat man overacting?
Pile-driving gags into submission like a loincloth-clad Nacho Libre, Black’s performance is manic and wearying – bad news in a buddy-buddy comedy.
It’s left to the adorable Cera to provide most of the laughs and all of the pathos. “Why all the genital mutilation?” he asks in that deflated fall-guy falsetto. Um, maybe because the writers ran out of ideas?
Between them, the filmmakers had a hand in Groundhog Day, Superbad and The Office USA, so they should know that when the knob gags tire, as they eventually must, the audience has to want to see what happens next. After all, you can’t laugh for 100 minutes, but you can care.