"FROM the halls of Montezuma to the spores of outer space, they will fight our country's battles anytime, anyplace . . . The Marines, sweating and swearing and valiant as lions, engage "Aliens" in this hell-bent-for-leathernecks sequel to the 1979 thriller by Ridley Scott. "Alien" was a classic of gothic horror, but "Aliens" is a blockbuster of epic combat, a high-powered, spine-tingling, interplanetary "Pork Chop Hill." Here, a few good men -- and in the year 2036, a few good women -- battle the blood-thirsty beings of the planet Archeron."