I might have what you're looking for, but it likely only works on single player games (or possibly if you host your own local game and just invite friends, then have them all make the same daylight settings. I don't know, I only do this in single player...
I have some modlets here:
doughs-modlets that are for making the game darker.
One Hour of Daylight -> Allows you to set down to 0 hours of daylight. You have to set this in the UI before starting a game.
Note: I personally use this , and I prefer 2 hours of daylight, just so I get to see some daylight and sometimes give myself a "breather" to escape a building or run to another town if I get trapped. It also lets you see some nice daytime visuals, which 0 hours daylight take away.
Note: There still is some "lighter" and "darker" parts of the day, even with 0 hours of daylight because of moonlight and "horizon light" coming in.
Also, if you're looking for a dark game, I have some more modlets that might help:
Buff Ambiance - Darker Nights -> Makes the nighttime darker. a19 isn't very dark normally. From my testing, based on moonlight effects, "day 5" night is the darkest in the 7 day cycle
Buff Ambiance - Darker Inside -> Makes the the indoors darker. Seems to give an effect of "i just got inside and have to adjust" as well as hopefully makes indoor conditions darker. I have been in attics in houses ( with no windows) and its almost 100% dark without some light source
Nerf Flashlights and Player Crafted Lantern -> Makes it harder to get flashlights, mostly for early game. The flashlights are really bright, and this forces you to find parts to craft them. Unitil then you have to rely on torches or lights in the game.
Punishing Weather - Core -> Doesn't change darkness, but limits visibility with more wind/fog/rain.
Also: there's another modder with a similar modlet that allows you to make daytime hours be 0 hours (and other settings options) :
claymores-modlets "More Options" modlet
Also: There's another mod I haven't tried called the "POI Light enabler" or similar. Its on these forums. It also only works per-user so its best for single player games (I believe). It basically lets you turn on/off any lights you find in POI's, which might be cool in a super dark game. I think its a DMT or dll mod so it might be a little different getting it to work.
