Excited to see Colin Farrell play the bad boy of the ancient world in Oliver Stone's Alexander when it opens this Thanksgiving? MGM Home Entertainment also hopes you're slightly deranged at least enough to be confused by the appearance of a movie called Alexander the Great in video stores. Same topic, similar titles, and, look, there's a rising young rebel thespian from the British Isles with a ludicrous blond dye job as the Macedonian who would be god! The difference is that this Alexander is played by Richard Burton, and he looks mortified. Robert Rossen's sword-and-sandal epic is opulent, chatty, and fascinatingly stiff, as if a bunch of grown men had been handed togas and told to play dress-up. Still, if it's not good history weren't there three major battles in Persia rather than two? it's great CinemaScope. A few years earlier, Rossen had left Hollywood after naming names for HUAC, and the director's penchant for scenes of intense emotional confrontation takes over the first half of Alexander. With our petulant young hero chafing under the reins of his warrior father, Philip (Fredric March), and hubba-hubba mother, Olympias (''the French Star Danielle Darrieux,'' according to the credits), it could be Rebel Without a Chariot. Eventually the son gets his own monomaniacal campaign to wage, and much fake blood is spilt, but Burton never registers much enjoyment in the dispatching of lesser men and nations. It's a closeted performance in both the characterization and the playing, with the conqueror brooding cryptically over lissome pals like Cleitus (Gustavo Rojo) and Hephaestion (Ricardo Valle). Compared with what Stone is supposedly up to, this one might as well be called Alexander the Straight.