Alone in the Dark
“I do not speak as I think, I do not think as I should, and so it all goes on in helpless darkness.” ― Franz Kafka
Makes it pitch dark and optionally always night. For extra immersion and challenge, turn off the minimap.
Try https://mods.factorio.com/mod/AfraidOfTheDark to get more options for dealing with the darkness.
Alternatively https://mods.factorio.com/mod/NightBrightness for a darkness adjustment mod with more options.
Enable - Uncheck this and save the game again if you want to remove the mod, or it will remain dark
Always night - Unless you find a way to get to the other side of the planet, you will always be on the dark side
Note: These are under startup settings, but can be changed before loading the game
The Unlicense (Public Domain), do whatever you want with this.