Attention nerdlings: "Paul"

Paul is all of the following: Working Title's idea of a reward to Simon Pegg and Nick Frost for their sterling work on Shaun of the Dead and Hot Fuzz; a film that could only have come out of (and might only play to) the convention circuit; a convention all its own, of the Stateside branch of the Simon Pegg fan club; an effects comedy, a bromance, a putative stoner flick. The paradox is that it should be several movies at once, and still disappointingly slight rather than seeming ambitious in any way. In form, at least, it resembles a road movie. Sci-fi writer Clive (Frost) and best bud/illustrator Graeme (Pegg) have decided to their annual pilgrimage to the Comic-Con convention in southern California as an excuse to explore America's UFO heartland. They're heading to the fabled Area 51 when their rented motorhome attracts the attention of another tourist: the walking, talking, computer generated extra terrestrial of the title - essentially a hipper Jar Jar Binks, voiced by none other than Seth Rogen.

From this point on, the trio are pursued across the American South by what appears half the roster of the New American Comedy: Bill Hader and Jason Bateman as FBI agents, Jane Lynch as a truckstop waitress, David Koechner as a trucker Graeme and Clive succeed in irking en route. Though the laugh aggregate (the gaggregate?) is marginally higher, Paul's MO isn't too far removed from that of Ricky Gervais's The Invention of Lying, in which - again - a hit English comedian signed up performer after performer, admirer after admirer, without stopping to think whether either party had material worthy of their participation. Upon reflection, neither clearly did.

With the relocation of the Pegg-Frost brand, we might have been hoping for some satire on modern American values comparable to that highly detailed form on English attitudes in which both Shaun and Hot Fuzz dealt. Yet Paul continually forsakes the specific for the broad: when our heroes kidnap a seasoned Bible-basher (Kristen Wiig), she's converted to foul-mouthed secularism in a flash, a process that yields but one throwaway laugh from her T-shirt (adorned with an image of Christ shooting Darwin in the head) and not much else besides.

The film reverts to the default mode of a Kick-Ass or Edgar Wright's Scott Pilgrim vs. the World, all nods and winks that'll doubtless go over big with nerds, and don't add up to anything much for the rest of us. There are flickers of tangible, winning ideas: the flashback that suggests Paul gave notes to Spielberg during the making of E.T., a roadhouse where they play the Cantina Theme from Star Wars, and the presence of white-uniformed sailors on shoreleave leads to an archetypal bar brawl. Yet too many of these homages don't do anywhere near a laugh: the FBI agents, for example, whose characterisation derives entirely (and mirthlessly) from the bantering cops in something like Men in Black.

It's a closed-loop of a film: all it tells us is that its makers have seen a lot of movies, and the only ending it can contrive for itself involves the characters receiving their own standing ovation before the assembled masses of Comic-Con. If you spot all the references, you may be able to send off for a girlfriend. Otherwise, as hinted by Paul's quest to return a teddy bear to its owner, the prevailing tone is childish, at best adolescent, director Greg Mottola reverting to the anything-goes knockabout of Superbad after the nuanced Adventureland. Amiable rather than funny, mild verging on the anodyne, there is one glaringly obvious audience for Paul beyond the convention circuit: extract the Tourettish swearing - which, in this context, really does come across as compensation for comedic deficiencies elsewhere - and I'm willing to bet nine-year-olds would love it.

Paul opens nationwide on February 14.