Simon Pegg, Nick Frost, Kristen Wiig, Seth Rogen

Directed by Greg Mottola

Never before has a film been targeted specifically for the Comic-Con crowd as “Paul.”  As Graeme and Clive – the card-carrying nerds played by Simon Pegg and Nick Frost, respectively – proudly make their way through the dense crowds at the famous human be-in known as the San Diego Comic-Con, the raunchy R-rated comedy announces its intentions and successfully caters to its audience with fun, appreciation and, most importantly, a ton of heart.

And that pretty much sums up the tone of the film, which transcends its demo to succeed as a highly enjoyable, often hilarious and surprisingly sweet early spring crowd-pleaser.  Though it lacks the clever wit that defined 2004’s “Shaun of the Dead” and 2007’s “Hot Fuzz” – the previous genre spoofs that Pegg co-wrote with Edgar Wright – it’s safe to say that “Paul” still fits the bill as an out of this world road-trip comedy.

San Diego is the first stop of many for British nerds Graeme and Clive, who have meticulously mapped out a list of supposed alien hotspots around the U.S.  While en route to the so-called “secret” hotbed of UFO activity – Area 51 in the Nevada desert – Graeme and Clive have a close encounter of the bizarre kind when they literally run into Paul: a real-life alien who’s been marooned on Earth since the late 1940s and is looking for a way to phone home.

But Paul is no ordinary alien (if aliens could ever be deemed “ordinary”).  Despite his familiar appearance – short, diamond-shaped eyes, slits for nostrils and an enormous head – Paul speaks English, swears like a sailor, loves pistachios, smokes too much weed and sounds an awful lot like Seth Rogen.  With trigger-happy federal agents hot on their tails, Graeme and Clive race against time to help Paul return to his mothership and get the hell off this rock.

Despite veering more towards the raunchy humor that defined 2007’s “Superbad” rather than the depth that underscored 2009’s “Adventureland,” director Greg Mottola further defines his talent for crafting harmless entertainment with “Paul” – nothing is really at stake here, except having a good time.  And while the funny screenplay co-written by Pegg and Frost is filled with references to sci-fi classics (most of them from Steven Spielberg and George Lucas), a bit more wit might have elevated “Paul” to the greatness of “Shaun of the Dead.”

But what really pushes “Paul” into the stratosphere is the level of charm and chemistry between its game cast members.  Pegg and Frost have an effective rhythm that goes a long way during the sillier moments, while supporting turns from the likes of Kristen Wiig (as a sheltered trailer park attendant) and Jason Bateman (as an uptight FBI agent) add to the endearing vibe.  And then there’s Paul himself, who, like his movie, has a heart so big that resistance is futile.