Initially intended to be a twenty-minute horror game, the developers continued to expand the game into an alternate reality game (ARG) involving cryptic messages and secret passcodes.

Simon "Ghost" Riley - A character in Call of Duty: Modern Warfare 2 and the main character of Modern Warfare 2: Ghost. Simon "Ghost" Riley (Reboot) - A character in Call of Duty: Modern Warfare (2024), Call of Duty: Modern Warfare II (2024) and Call of Duty: Modern Warfare III (2024).

Ghost appears as a main character in Call of Duty: Modern Warfare 2, Modern Warfare 2: Ghost, Call of Duty: Online, Find Makarov: Operation Kingfish, Call of Duty: Heroes, and Call of Duty: Modern Warfare 2 Campaign Remastered.