Bob Graham, Chronicle Senior Writer

BATTLEFIELD EARTH: Sci-fi fantasy. Starring John Travolta, Barry Pepper and Forest Whitaker. Directed by Roger Christian. (Rated PG-13. 117 minutes. At Bay Area theaters.)

John Travolta never ceases to amaze.

In his pet project, L. Ron Hubbard's ``Battlefield Earth,'' he has transformed himself into a green-eyed monster.

He's kinda cute.

Even with gravity boots that make him about 8 feet tall, an unruly mass of dreadlocks, cruddy teeth, eyebrows that point to outer space, a rubber suit that doesn't cover up his chunkiness so much as exaggerate it and breathing tubes that make him appear snot-nosed, which is a fair description of the villain he plays.

Travolta is a middle-management tyrant from a race of aliens called Psychlos, who have taken over Earth in the year 3000 to strip it of its minerals. Earth is their Siberia. They hate it, consider an assignment there worse than hell and can't wait to get away and blow it up behind them. If you kick the ``l'' out of Psychlos -- as cave-dwelling earthlings try to do -- they become Psychos, which is a good thumbnail description of the plot.

Did I say thumbnails? Travolta's are gross and pointy, like spades, emerging from wispy hair on his knuckles. And he thinks humans are ugly.

There is a kind of nuttiness at work in this great big comic book of a movie. It is a spacey demolition derby. ``Battlefield Earth'' needs to be approached by audiences in the same spirit Travolta approached the material. He's obviously getting a kick out of it.

Will it become a campy, sci-fi classic along the lines of ``Planet of the Apes''? Too soon to tell. Is it worth seeing once? Sure.

Travolta, who is the producer as well as star, had wanted to make movie of Hubbard's book for at least 15 years. There was only one catch: His career was in the tank. Ever since ``Pulp Fiction'' jump-started his professional life in 1994 and he followed up with a string of hits, including ``Get Shorty,'' ``Face/Off'' and ``The General's Daughter,'' he has the leverage to bring this movie off.

``Leverage'' is a key word among the Psychlos, too. A conniving, untrustworthy bunch, they are constantly playing dirty tricks on one another and, like lawyers, pulling fast ones with the language as they maneuver for power.

The security chief, Terl (Travolta), has a sidekick, played by Forest Whitaker (``Ghost Dog: The Way of the Samurai''), whose spacecraft is a few brain waves short of lift-off. Terl is constantly taking advantage of him. Their interaction becomes a weird Abbott and Costello routine.

Travolta's wife, Kelly Preston, appears all too briefly as his baldish Psychlo girlfriend, with a tongue that rolls out like a venetian blind.

NO `DIANETICS' CONNECTION

While we're getting personal, the late sci-fi novelist Hubbard, of course, is the guru of Scientology, and Travolta is one of his celebrity followers. Travolta has said that ``Battlefield Earth'' has nothing to do with Hubbard's ``Dianetics,'' the basis of Scientology, and is intended as pure entertainment. There's no reason not to give him the benefit of the doubt.

The film certainly plays that way. With director Roger Christian's every shot -- right up until the very last one -- tilted at an angle, it has the skewed perspective of a comic book. In this dystopia, Earth is in ruins, the exploitive Psychlos have covered what's left of Denver with an enormous greenhouse (so they can breathe their own polluted air) and the remaining human beings have reverted to cavemen.

With tens of thousands of pieces of glass in that Denver greenhouse, it is fair for a viewer to wonder how long it will take before they all shatter.

PEPPER REMARKABLE

Barry Pepper, the American sharpshooter in ``Saving Private Ryan,'' emerges as the leader of a guerrilla revolt by the earthlings

--he is called Greener, as in ``the grass is greener on the other side of the fence.'' Pepper's is a remarkable presence, but a viewer needs a leap of faith to accept the uprising by the ``man-animals'' against the Psychlos.

More effectively presented is the wary, uncomprehending relationship between the two races. Terl is always congratulating himself on his understanding of the lesser beings, and he is always mistaken. When he sees the starving humans eating rats, he assumes they enjoy it and tries to use the knowledge as leverage against them.

I have no idea if Hubbard was a fan of Richard Wagner's music dramas, but there are curious echoes of ``The Ring'': the giants, the exploited underclass, the greed for gold. The aliens, sent by the ``home office'' of a corporate state, are seen as gods by the earthlings.

PSYCHLOS ENJOY TORTURE

It's stimulating in ``Battlefield Earth'' that the aliens are mean -- none of that sappy ``E.T.'' religiosity. The Psychlos enjoy torture, including mental torture inflicted on one another.

Travolta sometimes adopts a condescending aristocratic accent and on occasion sounds as if he's doing a Bette Davis imitation, with clipped words on the edge of exploding.

When the humans or the aliens speak among themselves, it is presented in American English, but there are incomprehensible growls when they interact.

Greener is given a crash course in the Psychlo language by a Uriah Heep-like ghost. The knowledge is zapped into his brain via pinpoints of light shooting into his eyes. On two occasions, that light is turned directly on the audience.

Who knows what secret knowledge we have unwittingly absorbed. ..