Initially, "Beverly Hills Cop" was supposed to star Sylvester Stallone and was meant to be an action-packed film. The studio decided to go in an entirely different direction, and Eddie Murphy was in as Axel Foley, resulting in one of the most successful comedy franchises ever.
"Demolition Man" was a huge break for actress Sandra Bullock, as her role as Lieutenant Lenina Huxley was initially given to Lori Petty. The studio was dissatisfied with her dailies and Bullock stepped in, bringing some necessary naivete to the role, giving audiences a character to root for.