Sound of Silence

When we were discussing how to make scary games scarier for more people I was thinking about a video I had recently seen about an idea for a game called "Sound of Silence". It doesn't address how to make games scarier for more people, in fact, it sort of does the opposite. The idea is to make the game as terrifying as possible for an individual. It alters itself based on the fears of the player.

http://www.youtube.com/watch?v=wmMXXC_TdU0

I've played games that have multiple endings depending on the choices you make throughout the game, but the choices have always been made obvious. There are usually scenes where you decide an option (maybe out of three or four) of what to say or do as a response to a conflict in the plot. Sometimes these are based on morals (save someone, leave them, kill them) or based on strengths and weaknesses (power, defense, agility, etc). They usually affect what stats the character will have or if you have a "good guy" or "bad guy" ending. In the games I've played with options like these, the choices you were making were obvious and conscious. This is the first time I've seen a game where the game play changes depending on what you are drawn to or avoid in an environment. I feel like this would create a more natural and interactive experience that could be applied to many other games.