Like its four-armed Tharks and its ten-legged Calot, this adaptation of Edgar Rice Burroughs's series of sci-fi novels has too many moving parts for its own good. And it's weakest part is the most crucial. As the title ex-Confederate officer transported to Mars, Taylor Kitsch barely gets by with a Clint Eastwood growl and the special effects that allow him, because of the reduced gravity, to leap like a giant cricket. Embittered by the war, Carter at first refuses to take sides in the battle raging in his new digs until the princess Dejah Thoris (Lynn Collins) woos him into theHelium (the Martian city, not the gas) cause as they battle the world-plundering Zodangans. And don't forget the Therns, who are all-powerful, meddling, and don't give a shit. Derivative most obviously of Avatar but refreshingly less pretentious, Carter takes off when director Andrew Stanton (WALL-E) and co-screenwriter Michael Chabon don't take it too seriously.