Doom 2 is pretty well-lit for a labyrinth full of demons, and after 25 years its power to intimidate has perhaps diminished a little, but there's a solution! Night64K is a mod that turns out all the lights, forcing you navigate the darkness with flares.
Regular Doom 2 in the dark would of course be entirely impossible, so regular enemies have been stripped out and replaced by Shadows, nasty monsters that will invade your personal space and try to tear you to shreds.
You'll need to toss out flares to get your bearings and keep a look out for more Shadows, and they come in different colours, too, just in case you wanted to turn Doom into the world's most depressing nightclub. You can see it in action in the video below.
Night64K was made back in 2016, but modder DeXiaZ recently reuploaded it to ModDB, where you can download it now.