In the summer of 1990, Sierra's InterAction magazine ran a contest called "Be a character in King's Quest V". Entrants had to submit photos of themselves in clothing that would fit in with the King's Quest world. The winners Amanda Logue and Austin Hartman became the characters "Amanda" and her son "Austin"; customers Graham briefly meets in the Baker Bros. Bakehouse, and were featured in a one-page photo spread in a subsequent InterAction issue. Amanda and Austin do not appear in the NES version of the game.
There is hidden Easter Egg in the game: after Graham rides the sled in the mountains and it breaks, using the cape on the broken sled cause the sea monster to appear and push Graham into the chasm. However, this Egg works only in the diskette version of the game, much to the disappointment of many King's Quest fans who own the CD version only.
The diskette version of the game includes copy protection. A message will interrupt the gameplay whenever Graham is in the process of completing a crucial task; requiring the player to "help" Graham by casting a spell with Crispin's wand, using the instruction booklet to select the appropriate on-screen symbol. If the player selects incorrectly, Graham botches the task and the game is lost. The copy protection was eliminated from the CD version.
Roberta Williams initially disapproved of the series' gameplay switch from command line parser to point-and-click, because she felt it made the game less challenging for players than it should have been. Williams changed her mind when she watched her elderly mother try to play King's Quest III: To Heir Is Human (1986) and observed her having difficulty figuring out which correct nouns and verbs to input. Although the gameplay switch divided some fans upon release, Williams defended her decision in press interviews, stating: "My own mother couldn't play my games!"
At the screen where Cedric is kidnapped by a wolf, the middle mountain looks like the logo of Sierra On-Line. When using the "eye" icon on it, the game message says that it seems vaguely familiar to Graham.