King’s Quest IV is a graphical point-and-click adventure game done by Sierra On-Line in 1988. It’s one of the first commercially released PC games that supports sound cards instead of the built-in speaker. This game is also the only one that was simultaneously developed using both the old AGI engine and the later SCI engine, because Sierra was worried if low-end systems would be unable to run the SCI version. However, the SCI version outsold the other one, so the AGI version is quite rare today.
In this video, you can see the self-running demo of the SCI version.