It even begins at our mecca: San Diego Comic-Con, or at least a lot less crowded movie facsimile of it. That says enough about the backstory of Graeme (Pegg) and Clive (Frost).

Attending Comic-Con has been a (near) life-long dream for them, and since it's likely they were only going to make it to the U.S. once, they follow it up with a Winnebago drive cross-country to visit all the hot spots of alleged alien encounters, including the Black Mailbox, Area 51 and of course Roswell.

In their journey, they run afoul of two rednecks (David Koechner and Jesse Plemons), and for a bit, Paul looks like it could turn into a riff on Deliverance. But then they meet Paul, a stereotypical alien grey. At least until he opens his mouth and the strangely wizened voice of Seth Rogen pops out.

Now pursued by shadowy government agents led by Jason Bateman and a not actually surprising cameo, the boys have to get Paul to a rendezvous point with his people. After sixty years or so advising the government, the alien has outlived his usefulness and must get off-planet before his captors can dissect his brain.

Throughout the pursuit, the movie takes a skewed look at middle America, and its biggest flaw may be that its harshest jabs hit there. Koechner and Plemons are cartoony at best, in sharp contrast to the alien Paul being a rounded character.

And though a few lines of dialogue try to soften the blows, Kristen Wiig's Ruth Buggs and her father, Moses, stand for conservative Christianity in pretty cruel outlines.

It's funny, and it's not that Pat Robertson would have watched this anyway, but the movie still has a tendency to beat the proverbial dead horse on that one.

Paul himself could possibly revive that dead horse, just one of many nods to the science fiction (and fantasy) films that inspired and influenced Pegg and Frost. Director Greg Mottola acknowledges much of that influence visually, but when not paying homage, there isn't much of a visual flair to the work.

The direction is serviceable, and lets some very talented and funny actors do their best. It also has to be achievement to make an alien seem so ordinary – and that's meant as a compliment to both Mottola and Seth Rogen. As in Monsters vs. Aliens, it seems that voicework is really where Rogen can transcend people's preconceived notions about him.

What keeps the movie going isn't just the energy of its leads; they're actors who haven't quite forged personae beyond being funny and British. It's that they've written a smart script. Paul could have just as easily been a straight adventure, so the plot ticks along, even when it stops for reflection.