Games like Quantum Sleeper
Games like Quantum Sleeper include Outlast, SOMA, Darkwood, The Outlast Trials, and Little Nightmares II. We matched them by the tags players give Quantum Sleeper on Steam (Horror, Psychological Horror, Stealth, Survival Horror, and Dark): closest matches first, and among equally close ones the better-known games.

Outlast
Shared: Horror · Survival Horror · Psychological Horror

SOMA
Shared: Horror · Psychological Horror · Atmospheric

Darkwood
Shared: Horror · Psychological Horror · Survival Horror

The Outlast Trials
Shared: Horror · Psychological Horror · Survival Horror

Little Nightmares II
Shared: Horror · Psychological Horror · Dark

Little Nightmares
Shared: Horror · Atmospheric · Dark

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

Poppy Playtime
Shared: Horror · Survival Horror · Psychological Horror

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

Inside the Backrooms
Shared: Horror · Survival Horror · Psychological Horror

Lethal Company
Shared: Horror · Survival Horror · Psychological Horror

Outlast 2
Shared: Horror · Psychological Horror · Survival Horror

Five Nights at Freddy's: Security Breach
Shared: Horror · Survival Horror · Stealth

Visage
Shared: Horror · Psychological Horror · Survival Horror

Alien: Isolation
Shared: Horror · Survival Horror · Stealth

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

Dead Space
Shared: Horror · Survival Horror · Psychological Horror

Pacify
Shared: Horror · Psychological Horror · Survival Horror

ROUTINE
Shared: Psychological Horror · Horror · Atmospheric

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

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

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

Amnesia: The Bunker
Shared: Horror · Survival Horror · Stealth

Backrooms: Lost Tape
Shared: Horror · Psychological Horror · Survival Horror