Games like The Dark Inside Me
Games like The Dark Inside Me include Outlast 2, Fran Bow, Scorn, Sally Face - Episode One, and Little Nightmares. We matched them by the tags players give The Dark Inside Me on Steam (Adventure, Indie, Sexual Content, Nudity, and Horror): closest matches first, and among equally close ones the better-known games.

Outlast 2
Shared: Horror · Gore · Dark

Fran Bow
Shared: Adventure · Indie · Horror

Scorn
Shared: Sexual Content · Horror · Gore

Sally Face - Episode One
Shared: Indie · Adventure · Horror

Little Nightmares
Shared: Adventure · Horror · Indie

Clive Barker's Hellraiser: Revival
Shared: Sexual Content · Nudity · Gore

The Medium
Shared: Adventure · Horror · Sexual Content

Detention
Shared: Indie · Horror · Adventure

Lucius
Shared: Adventure · Horror · Nudity

Tiny Bunny
Shared: Horror · Dark · Atmospheric

Little Nightmares II
Shared: Adventure · Horror · Dark

Outlast
Shared: Horror · Gore · Adventure

Amnesia: The Dark Descent
Shared: Horror · Gore · Nudity

Mouthwashing
Shared: Horror · Indie · Gore

Hellblade: Senua's Sacrifice
Shared: Adventure · Atmospheric · Dark

SOMA
Shared: Horror · Dark · Atmospheric

Raging Loop
Shared: Adventure · Indie · Gore

MiSide
Shared: Sexual Content · Horror · Story Rich

FAITH: The Unholy Trinity
Shared: Indie · Horror · Adventure

Resident Evil Village
Shared: Horror · Sexual Content · Gore

No, I'm not a Human
Shared: Indie · Horror · Psychological Horror

The Cat Lady
Shared: Adventure · Horror · Indie

Rusty Lake Paradise
Shared: Indie · Adventure · Horror

ParanormalHK
Shared: Sexual Content · Horror · Nudity