Nobody can invoke helpless, frantic fear as well as Frictional. The Swedish indie studio is best known for the 2011 game Amnesia: The Dark Descent, but it’s also just synonymous with a specific kind of survival horror. Frictional games don’t have weapons. They’re slightly clumsy. They keep monsters in the corner of your eye until it’s too late. And they usually involve a whole lot of Lovecraft — not your basic Cthulhu-and-Necronomicon pastiche, but stories about men and women of science facing entities beyond their comprehension.

Frictional’s new game Soma, coming this fall, is most of those things. It feels slightly like a callback to the Penumbra series that Frictional published throughout the late ‘00s, but set in a creepy, abandoned underwater lab instead of a creepy, abandoned underground mine. Based on a roughly 3-hour preview, though, it might also be the studio’s most mature and sophisticated game yet.

A play-by-play walkthrough of Soma doesn’t sound all that original. Enter a room, read a thing, flip a switch or switch-like object, maybe flip another switch to activate that switch, go to a new room, and run away screaming if something tries to kill you. But that doesn’t capture how well it’s negotiated the balance between "walking game" and "adventure game." Soma’s demo doesn’t have physics puzzles or sequences of picking up and combining objects. Its kind of stripped-down gameplay is exactly what I didn’t like about Frictional’s last game, Amnesia: A Machine for Pigs — at the time, it seemed to lower the stakes and encourage linearity. In Soma, it lets the environment itself become the puzzle.

My tastes have probably shifted a little, but Soma also just seems more comfortable in its own quasi-walk-em-up skin. Set at the bottom of the Atlantic, the demo alternates between labyrinthine gunmetal corridors and the empty ocean floor, between bloodstained grating and the bright, encroaching flora and fauna of the sea. With virtually no interface or items to pick up, half the difficulty involves figuring out where you are and where you need to be, then getting there without alerting one of the eerie, robot-like creatures that appear to be the station’s last remaining inhabitants. Instead of accepting the dichotomy between exploration and challenge, Soma just turns up the pressure, until you almost wish you could take a break to stack boxes and mix chemicals.

There are a few stumbles that break the flow by seeming too scripted, and Frictional games have a history of getting less scary once you become familiar enough with their monsters. But it largely captures the perfect feeling of being incredibly curious about where you’ve ended up while wanting desperately to get out of there. The setting, a mysterious facility known as Pathos-2, is full of hints that something terrible has happened. But you’ll also see rough sketches, annoyed notes, and books or postcards that belonged to the old crew. It’s more physical and detailed than Frictional’s previous games — it almost feels influenced by Gone Home, which ironically started as a mod of Amnesia.

What it notably doesn’t feel like is similarly watery horror game BioShock. BioShock’s retro-futuristic stylings were, in their way, very cynical. It’s a series where having ideals usually leads to moral ruin, and the city of the future is built on a cracked and shoddy foundation. Soma’s straightforward "abandoned experimental site" premise, by contrast, quickly segues into a complex science fiction story that’s tragic but strangely hopeful. Both Amnesia games had grotesque third-act revelations, and Soma might be no exception. But the demo’s horror comes not from the darkness in humankind so much as the feeling that you’re facing something absolutely alien.

That includes whatever created the fleshy barnacles and lumbering monsters in Pathos-2, but it’s also the ocean itself, which might be the most frightening Great Old One of all. Frictional has tapped into the primal fear of our planet’s last unmapped frontiers, a place where life works by different rules and even the thickest glass and metal can’t erase our vulnerability. In this case, there just happen to be even bigger forces at play — and a plot twist that I really, really want to reveal but can’t. Which means that I also can’t wait for everyone else to play it. Just, no matter what the game tells you, keep the lights on when you do.

Soma will be released on September 22nd for PC and PlayStation 4.