 Unrepresented by management , Davis sent his script out unsolicited to agents and studios over the course of the next three years . Davis secured representation through his efforts and received a number of studio offers , but , in a story reminiscent of Sylvester Stallone 's experience with Rocky , he refused to sell the script unless he was signed to play the title role . He also resisted demands that Marty be made heterosexual . While Davis and director O 'Flaherty honed the script , Davis trained as a boxer to add to the film 's authenticity . The film was shot in Los Angeles on high @-@ definition digital video on a budget of $ 200 @,@ 000 and was O 'Flaherty 's feature debut . 
