 Around one hundred digital effects shots appear in the film, mostly  to create gore. The scenes involving objects coming into direct  contact with skin (like throat slitting, people getting shot in the  head or neck, or stabbings) were created digitally. The violence  that didnt involve direct skin contact (like people getting shot in  areas covered by clothing) were achieved practically.  Rob Zombie (qv) originally intended to create all of the special  effects using only techniques available in the 1970s, but time  constraints prevented this.