Games like Sphenoid
Games like Sphenoid include SOMA, Poppy Playtime, Outlast, Outlast 2, and Resident Evil 7 Biohazard. We matched them by the tags players give Sphenoid on Steam (Horror, Psychological Horror, Escape Room, Puzzle, and Dark): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Horror · Psychological Horror · Dark

Poppy Playtime
Shared: Horror · Puzzle · Psychological Horror

Outlast
Shared: Horror · Psychological Horror · First-Person

Outlast 2
Shared: Horror · Psychological Horror · First-Person

Resident Evil 7 Biohazard
Shared: Horror · First-Person · Survival Horror

Amnesia: The Dark Descent
Shared: Horror · Psychological Horror · Puzzle

Little Nightmares II
Shared: Horror · Puzzle · Psychological Horror

Little Nightmares
Shared: Horror · Dark · Puzzle

Inside the Backrooms
Shared: Horror · Psychological Horror · Puzzle

Escape the Backrooms
Shared: Horror · Psychological Horror · Escape Room

Resident Evil Village
Shared: Horror · Survival Horror · First-Person

Visage
Shared: Horror · Psychological Horror · Dark

Bendy and the Ink Machine
Shared: Horror · Puzzle · First-Person

Layers of Fear (2016)
Shared: Horror · Psychological Horror · First-Person

MADiSON
Shared: Horror · Psychological Horror · Dark

Scorn
Shared: Horror · Puzzle · Psychological Horror

Darkwood
Shared: Horror · Psychological Horror · Survival Horror

Garten of Banban
Shared: Horror · Psychological Horror · First-Person

Fran Bow
Shared: Psychological Horror · Horror · Puzzle

Sally Face - Episode One
Shared: Psychological Horror · Horror · Dark

MiSide
Shared: Psychological Horror · Horror · First-Person

Lethal Company
Shared: Horror · First-Person · Psychological Horror

Backrooms: Escape Together
Shared: Horror · Psychological Horror · Survival Horror

SILENT HILL 2
Shared: Horror · Psychological Horror · Survival Horror