Clive Barker's Undying carries the distinction as one of the first games to carve an expression of terrified horror in my face from start to end. I swore I'd never revisit it, but it's on GOG now for $6, an absolute steal for one of the best and truly frightful first-person survival horror games out there.
Clive Barker's Undying
When unloading a shotgunful of death or crushing a shrunken Pig Cop alien beneath your manly boots in Duke Nukem, you can always expect to hear a clever follow-up—quips that defined one of classic PC gaming's most memorable characters. Jon St. John, owner of the deep baritone fueling Duke's wisecracks, has reprised his role in a franchise spanning nearly 15 games, but he doesn't necessarily share Duke's pleasure of slugging bullets into warm bodies. In fact, during the latest episode of the Unlimited Hyperbole podcast (via PCGamesN), he revealed his aversion to guns and the violence they promote, saying, "I don't care for guns in general."