10 Genius Ways Video Game Developers Outsmarted You
3. Sound Effects Are Tied To NPCs - Half-Life
Sound design in video games is a whole other mess, as is perhaps evidenced no better than by Valve's groundbreaking FPS Half-Life, where the team had to get more than a little creative to make everything work.
Only players who pay the utmost attention will notice that NPCs such as Barney move their mouths whenever they press buttons on doors and other objects, and this is because the resulting sound effects are actually tied to them.
Due to unspecified technical issues, Valve were forced to attach these contextual sounds to the character activating the object rather than the object itself, resulting in the game's automated lip sync script also playing out and their mouth moving along with the sound effect.
It's easily missed if you don't happen to be looking intently at the NPCs as they're doing mundane things, and so it's yet another feat of masterful corner-cutting gamedev from the fine folks at Valve.