The halfling brains had been made into cheese by an insane (yet very friendly) fungus-demon-worshipping druid. The PC's didn't realize what they'd eaten until it was too late.
In one of my previous campaigns, the PCs had one of the best breakfasts of their lives, with the most amazing scrambled eggs...only to discover afterward that the eggs were from the intelligent lizard folk who were being addicted to drugs and enslaved as a source of cheap manual labor. The PCs were horrified and disgusted, and committed their lives and sacred honor to ending the enslavement of said lizardfolk. And one of the players nearly puked. I considered it one of my finest hours as a DM.
My games tend to head down darker roads. There's dealings with demons, drug use, rape (that happens off camera and isn't described in detail), slavery, racism, cannibalism, and so forth. It depends on the storyline. Even the M&M game I ran after it first came out was Age of Apocalypse with the evil turned up. I can't say that I use a lot of horror elements, since that's tough to do sometimes, but there have been some disturbing moments.
I think a game where you are chopping things up with swords and axes and flash-frying things with fireballs is going to be a little distrubing if you take a minute to describe any of the action. . .
But in my game, I love to describe the bizarre and creepy and get that look of disgust from my players.
Horror yes, but not bloody gooey 'horror'. I tend to go for a more subtle, highly atmospheric based terror rather than something overt in most cases.
That said, since my campaign and storyhours deal heavily with fiends, I refuse to water them down when it applies. One of the more recent updates to Storyhour 1 had a tower on Illsensine's corpse on the Astral which was literally painted on its interior surface with wardings, themselves drawn in such a way to form letters that spelled out bizarre poetry. And all of it was painted with the blood and viscera of a half dozen butchered githyanki, each of which appeared to have been made to watch while their companions were killed.
Fast forward a few plot arcs and I had the PCs trapped in a cavern in Pandemonium with a group of scholars, with -something- lurking out there in the howling darkness, slowly picking them off in increasingly disturbing ways, sometimes bloody, other times not. Not knowing what it was, and watching it start killing closer and closer to their camp without them noticing till after the fact, it seriously got under the PCs skin.
More than disturbing perhaps, my games are DARK to the point of being depressing at times. And yeah, I've made players cry. Have to ask my players though what their opinion is on my games, if they're disturbing in the same sense you think that yours might be.
Though, that said, I'll be descriptive with damage dealt by PCs or NPCs at times, beyond the 'he crits, you take 25hp damage, you are dead'. No, at an Enworld gameday I had a PC psion attack a Rutterkin, and deal a serious amount of damage. So I describe it as
the tanar'ri shrieks in pain as its eyes explode in a shower of blood, its brain boils and leaks out of its ears, nose, mouth and now empty eye sockets, and promptly collapses onto the ash strewn soil in a dead heap of flesh and bone.
