The central antagonist of "Amnesia: The Bunker," I clearly remember every encounter with the ape-like beast that inhabits the walls where the protagonist Henri Clément is trapped in the hell of World War I. Whether peering at it through the slats of a confessional with a mutilated chaplain, or using the last bullet from his precious revolver to drive it into the wall knowing it would come back angrier, every escape from this creature was harrowing and gratifying.

"Amnesia: The Bunker" is something of a new beginning for the series, maintaining a distinct sense of helplessness and foreboding while incorporating its vulnerability into a fully immersive sim. Plan your expedition from a "Resident Evil"-style safe room and explore a labyrinthine, non-linear world. [Think of the mansion in the Resident Evil game cube remake, and you'll go back and forth in search of keys while saving precious resources. As with the Spencer Mansion, I became painfully familiar with the layout of the bunker: "I remember this place like the house I used to live in, but it's filled with unspeakable horror."

My one criticism of the bunker is that the individual spokes are completely isolated from each other, connected only by a central junction with the Safe House administrative office. The wings themselves are each a nice, winding level, but after finishing the game, I thought that a more Metroid (or Mansion)-esque world that folded in on itself and included shortcuts between zones would have enhanced this already great setting. [As soon as the lights went out and the roar began, I had to contain myself from running to my happy place and fiddling with my Switch zonai device. But The Bunker stuck in my skull like nothing else, and even now, days after I finished playing it, I can't help but think about the experience.

Frictional's sound design is perfect for instilling a sense of dread and signaling the monster's alert level. The bunker has ambient, cavernous echoes punctuated by the squealing of rats, the occasional wild beast, and the earth-shaking sounds of German artillery. Each new sound would put me on edge, and one of my worst jump scares came not from the Beast, but when I tripped over a booby trap set by a dead comrade and detonated a grenade right next to my head.

The sounds that occur during the search increase the likelihood of monsters appearing through actions such as running, turning on a flashlight, or chasing away rats. There are always less obvious options. For example, you can break down a door with a cinderblock (oddly enough, cinderblocks have become one of the game's most valuable resources) or find a hidden ventilation opening in the next room, but it takes patience and keen observation to take advantage of this in the constant rush of time to play.

Running the bunker's generator (located in the safe room) and keeping the lights on generally lowers the risk of the Beast. The bunker is most frightening when all the lights are out and the Beast is out hunting.

Certain puzzles in the critical path require power to be on, and fuel efficiency is constrained not only by the bunker's random item placement, but also by limited inventory and storage space. The terror of the atmosphere is maximized by this frantic, turn-the-table-turning exercise of managing fuel, recovery supplies, grenades, and key items (all of which occupy one inventory slot each and do not stack).

Every option in The Bunker feels like a carefully calculated conundrum. Blowing off the door will get you to your destination quickly, but the Beast will surely come to you, and you'd better have a place to hide in case he does. Endemic mutant rats that feast on corpses with valuable locker combinations can be driven off with fire (flares or homemade torches), toxic gas, or flag grenades, but each time you do so, you risk consuming resources and attracting the Beast. The WWI-era revolver has a very painful multi-part reload, where one button is pressed to hold the cylinder open and the other button is pressed to load one bullet at a time. Besides, what if I later need that bullet when faced with a padlocked door?

I trapped the Beast, used gas grenades (once I found the gas mask), and hid in closets and under tables. There is freedom in this immersive sim in how you explore and react to the Beast, but it's not a sneaky power fantasy like "Thief" or "Dishonored" for a game of cat and mouse with an apex predator. I think "Alien: Isolation" is the only game that offers similar simulationist depth and strategic options along with this very specific "feeling of being hunted.

But instead of the lengthy campaign of "Isolation," "The Bunker" is this perfectly compressed diamond, just you, the Beast, and the terribly scary place you are trapped in together.

As opposed to the myth-expanding psychedelia of "Amnesia": it's like a side story to "Amnesia," or an episode within a larger setting, or just a hint at the series' unnerving lore and Lovecraftian alternate dimensions. As much as I love the Philip K. Dick-esque mind-bender of a friction assassin, the more straightforward thread of "The Bunker" is elegant, finally piecing together exactly what happened and what role the protagonist, Henri Clément, played.

On top of that, I must commend the use of notes in The Bunker. In horror games and immersive sims, diary and dictaphone recording is one of the most overused techniques in games, but the implementation in "The Bunker" feels fresh. The Bunker's implementation of the diary and dictaphone is a new and exciting one: the compelling mystery of waking up in an empty bunker, the extensive and strange loveliness of the now-deceased French soldiers, and the tight time frame that unfolds over a few key days between May and July 1916. The notes can be sorted by date and by author, and I was like a little gumshoe, going back and forth between the two, trying to figure out who did what to whom and when. [The system-driven survival and the random placement of items and traps make every escape from the safe room unpredictable and unnerving, no matter how familiar you are with the game. The difficulty, danger, and stifling atmosphere of the bunker add to the pressure and "Eureka" potential of the immersive sim experiment. As you master the tools and discover the hidden pathways, you feel like a bolt-action French version of MacGyver, but a minute later the lights go out and you are suddenly a scared boy pointing a single bullet into the disturbingly loud void of a helpless facility.