I really liked the atmosphere in this game, and I thought that making the environment semi-transparent when the player walks behind something was a cool solution for increased visibility.
The only thing I was confused about was the presence of the eye indicator in the first two rooms with the absence of guards. Once the enemies showed up, I realized that the indicator probably showed up whenever I stepped into the light, but it made it seem like I was in danger when there weren't any guards around. It was unclear to me why I could walk through the first two rooms without consequence.