As voiced by Dwayne "the artist formerly known as The Rock" Johnson, astronaut Chuck Baker is the paragon of all-American achievement -- that is, until he conquers a far off world with an unexpected population, one inexplicably steeped in our '50s-era culture and terrified by the prospect of an alien invader in human form. More unfortunately for us, Chuck has landed smack-dab in the middle of Planet 51, a short-sighted assembly of sci-fi references and scatalogical humor that should nonetheless placate undemanding tots and, by extension, their undiscerning parents for ninety minutes or so.

The basic premise is lifted from The Day The Earth Stood Still, as green-skinned astronomer Lem (voiced by Justin Long) has to hide the new visitor from the military that stand between him and his ship. Chuck harps on relentlessly about "the right stuff," as if today's kids know their Gus Grissom from their Buzz Lightyear. We get an alien pet with a tongue within a tongue (instead of a mouth within a mouth) that urinates acid (instead of bleeding it). There's your token E.T. "over the moon" visual cue, and forgive me if I imagined a 2001 reference that actually wasn't in there (although I'm fairly certain a Singin' in the Rain bit was). It all just sort of blurs together after a while.

Oh, and just in case you feared all of that might go whizzing right over the little ones' heads, there's a Macarena joke and a Facebook reference. Welcome to 2009, y'all.

Writer Joe Stillman was one of four writers to receive an Academy Award nomination for their snappy Shrek screenplay, but by the time we get to corks being offered as butt plugs to prevent probing and an exposed (off-screen) penis being mistaken for an antenna, I can't help but wonder if he isn't that group's answer to Jason Friedberg and Aaron Seltzer being touted as two of the six writers of Scary Movie (you know, the worst ones).

Beyond all that, the script fails to justify why some planet unknown to ours would speak English and be seemingly stuck in a culture identical to our own in the 1950s -- it's simply reason enough to have the role reversal scenario play out amidst a relentless soundtrack of sugar-coated pop covers and a wardrobe of era-appropriate shirts (although not a single creature in sight bothers with wearing pants). Did we send some sort of Americana capsule to this planet that caused the white picket fences and the round convertibles and the duck-and-cover drills? Is there any sort of implication about our country's knack for colonization, before the era and since? Nope. Nothing. It's retro just because it can be.

Johnson could voice cocky swagger in his sleep, and might as well have; same with Long and whiny panic. Gary Oldman earns a paycheck as a generally threatening general, while John Cleese does likewise as his lackey scientist. Jessica Biel happens to be the love interest, though she's more often than not keeping company with an aggravating hippie equivalent (Alan Marriott). Seann William Scott plays Long's initially paranoid pal who falls hard for Johnson's own sidekick, a rock-collecting space rover named... Rover. (Was it legal to have creature-machine relations in these fake-fifties? Oh, never mind...)

To some extent, Planet 51 does demonstrate how the bar for mediocre computer-generated animation has been raised, if only in terms of visuals. Clothing textures or fire dynamics simply couldn't have looked this good a decade back, and it doesn't take Pixar to make a cartoon pretty. It does, though, take them to make a cartoon matter, and knowing full well that Up is now on DVD or that the new old-fashioned likes of Fantastic Mr. Fox will soon by playing on a neighboring screen (if not already) means that I can't really recommend something this lackluster with a good conscience.

Sure, it's bright and shiny and will keep your kids stationary for an hour and a half, but parents? Try and hold out for the intelligent 'toons. I promise that they're out there, waiting to be discovered by you and yours.