The face is the window to the emotion of on-screen characters. When you watch a movie the expressiveness or lack-of will tell the audience what the characters are going though and what they are feeling. This has always been a problem when it comes to video games. From the first games on the Atari, when the characters lacked any emotional visual cues, interpretation was the only tool to help build a connection. Now that games are moving more and more into a realistic visual style emotion is more important then ever. Seeing a character on-screen with dead eyes or puppet like mouths is no longer permitted and can destroy emersion for the viewer.