[Theory] Drastic dark areas?

[The chaser]

Or... you can do 2 things:

1: Fading out, changing the global fog and fading in. (Meh.)

2: Creating particle systems at entities (like sewer_fog) with black color, and, slowly, making them so they get close to the player (with timers). So, making more areas, if you get nearer to the darkness, you die. (I love this one)

My dream is to be a film director, so I always get more and more evil ideas for the horror genre
If you need help with ideas, tell me, Damascus.