It's a sign of a good horror game when the mere act of holding down the W key to progress through the next hallway requires you to remind yourself “You're not going to die. It's okay. This isn't real.” Such is the case with Amnesia: A Machine for Pigs. But unlike its predecessor, the scares aren't what make it so memorable and worth your time.
A Machine for Pigs moves Amnesia's timeline along from The Dark Descent's 1839 to 1899, ditching the Teutonic Castle Brennenburg for a sprawling factory complex in the heart of London. Electric lighting has removed the original's tinderboxes and fuel containers. Your only lantern-related concern will be deciding whether it's more important to see or stay hidden. Descent's sanity system has also been stripped out, along with collecting laudanum to recharge your health.
The result is a much simpler game, mechanically. But you won't find yourself missing the old systems. You won't have time to miss them while dealing with the shambling enemies that wait for you in the darkness. And whereas Dark Descent most often forced you to run and hide, most of Machine for Pigs' malignant horrors will have to be actively circumvented. This serves to build tension, but at the same time, takes some of the mystery out of the equation. In the majority of encounters, you will know where the enemies are, and they won't know where you are.
Unless you screw up. If you screw up, then they will know where you are. Then you will be screaming. And then you will be dead.
All things considered, A Machine for Pigs simply isn't as terrifying as Dark Descent. But it's terrifying enough to be worthy of the Amnesia label, and has enough interesting ideas elevating it to stand on its own as an exceptional experience. It's difficult to say anything about the game's final act without spoiling it, other than that it's fantastic and goes places you would never expect. There are fewer “water cooler” scares that you'll talk about with your friends, but the ending is likely to be discussed at length in the same fashion as BioShock Infinite.
Dark Descent distinguished itself by using helplessness to explore the emotion of fear. A Machine for Pigs adds to this palette, exploring the connections between fear, rage, and sorrow. At times, it even ventures into how strong motivations can transmute horror into a sense of empowerment—all without compromising the game's conflict-limiting mechanics. Dark Descent took you on a steady journey into an ocean of madness. A Machine for Pigs will hold your head underwater until you're about to drown and then bring you back up for air, again and again. And one of those times you resurface, you may discover you've learned things about yourself other than the fact that you need a new pair of underpants.