The video game which is central to the movie had already been in development as production of the film began (the game then named "Agent X"); when Atari was consulted to provide a game as an element of the movie, they tweaked "Agent X" and renamed it Cloak & Dagger. Dabney Coleman's character was then named "Agent X" in the movie. The game saw limited arcade release.
The Cloak & Dagger game screens are mostly from the arcade version, and not the Atari 5200 game console as it would appear in the film. Although an 5200 version of the game was planned, it never was released due to the video game crash of 1983 and eventual sale of Atari. The arcade version of Cloak & Dagger appeared in 1983 prior to the release of the film. Next to the Cloak & Dagger games are boxes for the 5200 version of Tempest. Like the 5200 version of Cloak & Dagger, this game was never released.
The Gamekeeper is an actual shop located in the Glendale Galleria in Glendale, California; a few miles from Universal Studios. The shop originally specialized in sophisticated role-playing games, such as the popular Dungeons & Dragons series. Since the time of the film it has relocated to a smaller store space within the mall and sells mainly mainstream board games. There are now also several franchise locations at other malls around the country.
Because the Atari 5200 version of "Cloak & Dagger" wasn't complete during filming, the cartridge props are actually other 5200 games with a "Cloak & Dagger" label stuck on them. The arcade game was complete by that time, and the signal was piped into Morris's monitor whenever he played. You can actually see the upright game cabinet standing next to Morris's computer setup.
Although the movie has gained a reputation for being something of an Atari 5200 commercial, there is a ColecoVision, the 5200's main competitor, visible in the main room of the Game Keeper. It's visible at the top of the screen as Davie is collapsing the walkie-talkie's antenna after talking to Rice.
The elderly couple in the film (John McIntire and Jeanette Nolan) both had parts in the original Psycho (1960). Richard Franklin directed the sequel, Psycho II (1983). Henry Thomas would go on to play young Norman Bates in Psycho IV.