I'd say Fear and Hunger is much more A/O than GTA or Witcher. Those games are built more around cathartic release; I wouldn't even call "Witcher" horror. The worse scene in Witcher 3 is the "Staked witch" scene, which is disgusting and pulls at the feelings; but it leaves players with greater resolve and empathy. In F&H, the harvestman was so much worse. Heck, even the consensual sex left a horrific pit in my stomach. The naked, dead strung up bodies, the "anal bleeding", limb loss, severed breasts & genitalia, cannibalism, self-harm, the helpless depression you just don't come back from...
Man, I love this game but I sure don't want my kids touching it before they're 18.