Frictional’s Amnesia games are fueled by guilt, and Amnesia: The Bunker — the latest installment, released today — is no exception. The Bunker has all the hallmarks of the beloved horror series: a nigh-invincible monster that stalks the player, a clunky interface that forces you to grapple with items physically, a historical setting with a Lovecraftian twist, and a protagonist who has forgotten something terrible.

But The Bunker is a marked departure from a long-established formula. Set in the trenches of World War I, it mixes Amnesia’s adventure game roots with a messier and more open-ended immersive sim design. It’s one of the series’ most unforgiving and least approachable entries — yet, at times, one of the most interesting.

Frictional described The Bunker as “semi-open world” last year, but that’s perhaps the worst description I could summon. The game is impossibly stifling. After 10 minutes of open-air trench warfare, your protagonist, part of the French armed forces, reawakens in a darkened bunker. The only exit has been sealed, and a supernatural creature is roaming the tunnels, tracking every noise you make. Your goal is to get explosives and blow the bunker open — a process that requires bypassing locks, grates, grenade traps, passcode combinations, and of course, the ever-present monster. Nearly the entire process takes place in five cramped areas, including a hub that holds a save point and a gas-fueled generator.

This generator is the eponymous bunker’s faltering heart. When it’s turned off, huge parts of the levels are pitch-black and barely navigable. There’s a flashlight, but it requires near-constant, noisy winding. And the creature seems to just hang around without the generator. Anything but a short trip is difficult in darkness.

I could make sense of this narratively; the generator’s sounds mask your own footsteps, maybe. (I’d say the light keeps the monster away, but electricity flickers off around it, like the puppets in Thief: Deadly Shadows’ Shalebridge Cradle.) It’s more useful to note that The Bunker punishes you for not engaging with its systems. The original Amnesia: The Dark Descent triggered “insanity” effects if you stayed in the dark and encouraged you to light candles and lanterns, but the effects were largely cosmetic and, with practice, ignorable. The Bunker is crueler, and not just with light. If you get injured and don’t heal yourself, you’ll start attracting dangerous cat-size rats. If you see a dead body in a corridor, it, too, will draw rats unless you burn it, wasting precious fuel. I once got so fed up with a rat cluster that I considered starting over.

Like the fuel, most items have multiple purposes, including a pistol that I believe marks the first usable gun — though not the first weapon — in Frictional’s canon. Empty bottles can be thrown as distractions or crafted into Molotov cocktails. Grenades can stun the creature and drive it off temporarily but also blow open wooden doors. Everything is painfully rare and must be carried in a tiny inventory, including a series of tools you’ll need to unscrew grates and cut chains. While certain areas are only accessible with these tools, others can be reached in multiple ways, like shooting locks or busting doors open with a brick. But like running or doing almost anything that makes noise, these methods will attract the creature and force you to hide or fight.

The experience is different from Amnesia’s usual puzzles and exploration. There are still several straightforward get-this-item-in-this-order challenges, but even the simplest actions require tradeoffs. Do you run and risk detection or walk and run the generator down? Do you bust down a door to get a map or save your equipment and your time? The original Amnesia had a classic point-and-click adventure game feel, but The Bunker is reminiscent of a stripped-down Thief, Deus Ex, or Dishonored; it’s got more classic Harvey Smith in it than last month’s actual Harvey Smith game Redfall. Like the first Amnesia, The Bunker supports making your own levels, and there’s a lot of potential for clever fan missions here.

The downside is that it lacks the earlier Amnesia games’ grandeur. The Dark Descent, while it’s about a dozen years old and showing its age, was set in a gorgeous castle whose levels ranged from cramped mines to lofty stone halls. Rebirth, from 2020, was full of eerie eldritch landscapes. The Bunker is relentlessly small and ugly. The first moment I came up for air felt extraordinary, and it was a narrow strip of daylight looking out into no-man’s-land — I left quickly, fleeing the ping of bullets that may or may not have posed a threat to me, and stepped straight into a grenade tripwire.

This makes The Bunker much less fun aesthetically, but it fits the setting, and so does the game’s narrative. Until now, most Frictional stories have dealt in larger-than-life choices: destroying a strange alien race in the Penumbra series, making human sacrifices to hideous gods in The Dark Descent and Rebirth. But The Bunker’s pivotal decision, made before the game begins, is as petty and unconsidered as you’d expect from one of humanity’s most senselessly destructive wars. Your protagonist later laments he barely weighed its risks at all.

I wasn’t as moved by it as I was by Soma, which I still think is the studio’s best work — a perfect fusion of atmosphere, story, and puzzles. The Bunker simply requires too much strategic thinking and repetition for the narrative to hit hard. The ending screen told me I completed my run in under six hours, but that’s not counting several more hours of unsaved trial and error, during which I would run around stumbling across traps and items, noting their locations, and reloading.

I will confess: I’ve finished virtually everything Frictional has ever released, and I hated playing parts of this game for review. It’s intensely stressful, and you can work your way into a position where it’s tempting to restart. It’s not obvious which obstacles can be cleared in multiple ways — why can you shoot a padlock to open it but not a chain? The HPL Engine’s deliberately obtuse interface makes parsing its mechanics even tougher.

But the game has stuck with me. Its few moments of real open space are haunting, and one encounter near the end subverts everything you expect from Amnesia’s monsters. I’m intrigued by the prospect of replaying it to explore more thoroughly and seeing what fans do with its systems, although I’m not sure when I’ll return.

The Bunker feels like a studio moving out of its comfort zone — and taking players with it.

Amnesia: The Bunker launches June 6th on the PC, PlayStation, and Xbox.