This game somehow reminded me about that time the rest of my usual group of friends thought it would be a
great idea to go into the forest on the cloudy night of a new moon.
From that
wonderful experience, I think a game that has darkness as its central motif needs to have two things:
- A very slow pace.
- Good locational/positional sound design.
The reason for the first one is very much akin to the maximum pace anyone can walk when they have limited vision. This was certainly true of us, given that we could really only see so far ahead of ourselves, and a forest (unlike its usual video game incarnation) is usually very overgrown and cluttered in feeling. (Much like your procedural generation here.)
The reason for the second one is that when you have little to no idea what direction is the one you came from, (and in darkness, this happens after a while in first person view,) even the slightest nonambient sound could promote panic, both on a rational individual level, as well as the
easily excitable group.
Games like Minecraft and Terraria have it more as a "populate darkness with light" deal, promoting a "colonization creep" into the unknown. In a game without a relative abundance of light sources, your best bet is to promote a slow sense of fear. You, after all, are surrounded by the unknown, and even you take what is unknown and make it known, time will only turn it unknown again.
That said, this does not necessarily need to be a horror game. It can
unnerve, but it need not horrify.
Of course, this is the experience of darkness from the perspective of someone who grew up in the country. I'd imagine someone who grew up in a town or city would have a different notion of darkness - less as an "all prevailing, silent, uncaring" thing, and probably something which operates more on a "malicious" social level, maybe.
