 According to the interview with Simón in "Pieces of Juan" (on the Grindhouse DVD version of the film), the director says that none of the female stars of the film knew how to play tennis, even though they were supposed to be portraying "professional" players.A tennis coach had to be hired so that they could learn to lob the ball in a convincing enough manner to make the film believable.Simón also revealed in the interview that he is proud of the visual effects in the film, especially that a pig carcass was used for the effect of the chainsaw cutting through a young woman's stomach and the slaughterhouse guts used.