I played through the game 2/½ times before I realised that I had played it with the wrong gamma settings!
The default setting is set too high. After lowering the gamma to one step from the furthest left of the slider I had a much greater experience. Each light in the environment creates the atmosphere from the movie perfectly now, they are more pronounced and vibrant. The flashlight has to be used now because the environments are darker, on Nightmare difficulty you will run out of batteries.. And most importantly, the alien feels more like a shadowy entity lurking around, harder to spot.
Playing last survivor on Nightmare difficulty with the correct gamma setting is really quite the heart pumping experience.
