Heavily fortified with adamantium, testosterone and CGI, "X-Men Origins: Wolverine" is a sharp-clawed, dull-witted actioner that falls short of the two Bryan Singer-directed pics in the franchise but still overpowers 2006's "X-Men: The Last Stand." For all its attempts to probe the physiological and psychological roots of its tortured antihero, this brawny but none-too-brainy prequel sustains interest mainly -- if only fitfully -- as a nonstop slice-and-dice vehicle for Hugh Jackman. An unfinished print leaked online weeks before the film's May 1 Stateside release will prove a mere flesh wound to Fox's B.O. haul, which should be muscular locally and abroad.