"Escape From Planet Earth" is a kind of parallel universe to "Planet 51," the 2009 animated comedy centering on an astronaut marooned on an alien world and his struggle to get home.

The plot of the new movie is nearly identical to that of the earlier film, except everything is flipped. Here, the astronaut is a blue-skinned E.T. named Scorch Supernova (voice of Brendan Fraser) who has been captured by the U.S. military.

After crash-landing in Area 51, Scorch is taken by the military, which throws him into a holding facility, along with every other little green man (and woman) who has ever had the misfortune to run out of dilithium crystals in the Nevada desert.

Like "Planet 51," it's a cute premise. But the movie doesn't aim any higher than cute. Its phasers aren't set on "stun" but on "something to occupy the kids while Mom and Dad pick up a few things at the mall."

As such, it's a success, if a less than rousing one.

The highlights include "Star Trek's" William Shatner, who lends his distinctive voice to General Shanker, the bad guy in charge of the base where Scorch is being held. Sofia Vergara also stands out as Scorch's sexy alien love interest, Gabby Babblebrock.

But it's Ricky Gervais who really shines, as the voice of a talking mainframe computer on Scorch's home planet, Baab (pronounced "Bob"). Even toned down for a PG audience, Gervais' trademark British snark lends "Escape" a lot of its low-key charm.

The rest of the voice cast is merely serviceable, with Sarah Jessica Parker, Rob Corddry, Jessica Alba, George Lopez, Jane Lynch, Chris Robinson, Steve Zahn and Chris Parnell failing to make much of an impression in their roles as miscellaneous aliens and humans.

Part of the problem is that the characters are somewhat generic. That's a weird thing, considering that many of them are visually out of this world. Lopez's Thurman, for instance, is a slime-covered creature with three eyes. The cold look of the computer animation renders him more bloodlessly than is necessary, even for a character that resembles a giant banana slug.

Just like its hero and his grounded starship, "Escape From Planet Earth" is, for much of the film, a decidedly earthbound adventure that doesn't take off.