Originally conceived by Aykroyd as a futuristic, interdimensional adventure titled Ghost Smashers , the script was heavily revised by Ramis and Reitman to make it affordable and relatable.
Speaking Humor to Power – Bradley J. Birzer - Law & Liberty Ghostbusters(1984)
: Reitman employed a "domino theory" of storytelling, leading the audience through credible choices—like getting a bank loan or hiring a fourth member, Winston Zeddemore —to make the eventual arrival of a giant marshmallow man feel earned rather than absurd. A Counter-Cultural View of Authority interdimensional adventure titled Ghost Smashers