As it turns out, Alan Wake began life as a “survival” game in which players needed to make the most of the world’s daytime hours. While the sun was out, you’d be expected to gather resources and create defensesfor example, hit up a gas station, then return to a safe haven and dump that gas into your generator, which is connected to your array of protective nighttime lights. Once the world turned to night, zombie-like “shadow” monsters would come out to attack.
Source: N4G PC War Stories: Alan Wakes transformation emerged from a two-month sauna