The trivia item below may give away important plot points.
According to producer Steven A. Jones, the original filmed ending has Milo beating Mad Dog in their fight. But test audiences could not accept seeing Robert De Niro getting beaten up by Bill Murray. Universal insisted that the fight scene be reshot and the film was delayed for a year. De Niro and Murray had taken the roles specifically because they were different than the type of roles audiences expected of them. The test audiences also felt Glory was an unsympathetic character so further reshoots were done to portray her as a victim of Milo's control.