Games like SUBJECT 33
Games like SUBJECT 33 include SILENT HILL 2, SILENT HILL f, Five Nights at Freddy's: Security Breach, Darkwood, and SOMA. We matched them by the tags players give SUBJECT 33 on Steam (Action, Adventure, Horror, Psychological Horror, and Puzzle): closest matches first, and among equally close ones the better-known games.

SILENT HILL 2
Shared: Horror · Psychological Horror · Story Rich

SILENT HILL f
Shared: Horror · Psychological Horror · Action

Five Nights at Freddy's: Security Breach
Shared: Horror · Multiple Endings · Adventure

Darkwood
Shared: Horror · Adventure · Action

SOMA
Shared: Horror · Psychological Horror · Story Rich

Little Nightmares II
Shared: Adventure · Horror · Puzzle

Poppy Playtime
Shared: Horror · Puzzle · Psychological Horror

Inside the Backrooms
Shared: Horror · Psychological Horror · Puzzle

Alan Wake
Shared: Action · Horror · Adventure

The Evil Within 2
Shared: Horror · Psychological Horror · Action

Little Nightmares
Shared: Horror · Adventure · Puzzle

Escape the Backrooms
Shared: Horror · Psychological Horror · Adventure

The Beast Inside
Shared: Adventure · Horror · Action

Fran Bow
Shared: Psychological Horror · Horror · Adventure

Sally Face - Episode One
Shared: Psychological Horror · Horror · Story Rich

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

SILENT HILL: Townfall
Shared: Adventure · Action · Horror

Mouthwashing
Shared: Horror · Psychological Horror · Story Rich

Bendy and the Dark Revival
Shared: Horror · Action · Adventure

Outlast
Shared: Horror · Psychological Horror · Survival Horror

Detention
Shared: Horror · Psychological Horror · Adventure

MiSide
Shared: Psychological Horror · Horror · Story Rich

Resident Evil 7 Biohazard
Shared: Horror · Action · Survival Horror

OMORI
Shared: Psychological Horror · Story Rich · Horror

