This is not the first time I’ve heard this. In another discussion thread I read a year or so ago someone was asking “how far is too gory”? (Sound familiar no?) and I think this was mentioned there too. Basically you lay the groundworks for your plot/story, tell the player what is going on, possibly even start their imagination with a short description of something in the scenery but intentionally become more vague in your descriptions and let their imagination do the work. This allows for those who don’t want the scene to become dark and for those who want the scene to become dark to both be satisfied.
EDIT: this could be seen in a story if someone were to write “you are walking in a straight line down the right side of the road. The birds are chirping loudly as the morning breeze tries to blow you into the buildings on your right. The streets are full of people as they are all walking to work, or maybe to pick up food for the day. Your eyes begin to sting from all the dust. Then you hear it, a bullet flies into the head of the woman in front of you, killing her before she even hits the ground.” Here you can see someone who wants it to be more gory would see blood splattering and gray matter everywhere, maybe they even get splattered with blood and brains. While the person who wishes for a more clean death would see that.
I understand this most likely doesn’t work for all conditions and therefore doesn’t answer the original question fully but as a general rule; this is always my first choice, with gore or other dark themes.
Here is the topic I was talking about: