Roman Polanski's first feature, ''Knife in the Water'', made when the director was 28, is impressive enough because it was shot on a shoestring budget -- mostly on a sailboat bobbing on a lake -- yet the film still looks visually stunning more than 40 years later. But what makes this debut truly special is that it feels instead like the work of a seasoned director hitting full creative stride. About a well-to-do couple (Leon Niemczyk, Jolanta Umecka) who embark on a boat outing with a brash student they picked up hitchhiking (Zygmunt Malanowicz), the film languidly swirls with subtle undercurrents of sexual tension, macho gamesmanship, generational distrust, and class antagonism, until the emotions boil over in a moment of violence. Polanski captures the three-character dynamic in bold, packed images that have retained their edgy vibrance. EXTRAS A new making-of doc is highlighted by Polanski's anecdotal recollections (including the revelation that he chucked his storyboards before filming began and created his striking compositions as he went along). A second disc full of the director's mordant, often disturbing early short films offers us a rare glimpse at the formative stages of a unique filmmaking sensibility -- with this, the set achieves true collector's status.