The films of director William Friedkin (The French Connection, The Exorcist, Sorcerer) have been called many things over the years, but "subtle" has never been one of them. While his brash, purposely nuance-free style can sometimes prove overpowering, when it clicks with the right material, it booms brilliantly. Killer Joe, Friedkin's reunion with playwright Tracy Letts (Bug), finds the director's in-your-face expressionist tendencies working like gangbusters, propelling this black comedy to places where most movies fear to tread. The laughs become winces, and vice versa. Letts's script (adapted from his play) follows a Texas bottom feeder (Emile Hirsch) with some serious gambling debts. Looking for a way out, he teams with his dim dad (a hilarious Thomas Haden Church) to hire a legendary hit man (Matthew McConaughey) for some dirty work. When the duo fail to come up with the collateral, however, Killer Joe sets his sights on Hirsch's beautiful sister (Juno Temple). Things go downhill at warp speed from there. Trafficking in bad taste from the very first scene (Gina Gershon makes a sleazy entrance for the ages), Friedkin and Letts take a no-holds-barred approach to their low morality tale, depicting even the darkest moments with overwrought relish. The already unstable mood is only boosted by the endearing scuzziness of Hirsch, Temple's lovely space cadet, and the fantastic Church, who deadpan annihilates every line and reaction shot tossed his way. Ruling the roost, however, is McConaughey, who spikes his trademark charisma with layers of serious menace, creating a villain who can seemingly do anything at any given moment. In a movie where virtually every character has an aura of 30-weight motor oil, he shines the darkest.