In the early 1980s, Sierra was at the forefront of the move from text adventures to adventures of the graphical kind—first with Mystery House, and later a string of games made in the studio's own Adventure Game Interpreter, like the first King's Quest and its immediate sequels. AGI allowed for sound effects, music, and 16-color vector graphics, depicting protagonists who moved around scenes with the arrow keys. You still had to type "lift plank" and "get ring" to interact with things, but you had something nice to look at in addition to the paragraph of text you'd get by typing "look" in each new location.
AGI's heyday lasted until 1988 when it was replaced by the Sierra Creative Interpreter, an updated scripting language that would eventually allow for hundreds of colors and digitized voice in games like King's Quest 6. Generally considered the best of the series, King's Quest 6 does still have a few dead ends you won't immediately know you've blundered into by not talking to a certain person or picking up the right object at the right time—an unfortunate hallmark of the series—but there are less of them overall. If you fondly remember one King's Quest game from your youth, this is probably the one.
