Games like Penance
Games like Penance include SOMA, Still Wakes the Deep, OMORI, Mouthwashing, and Sally Face - Episode One. We matched them by the tags players give Penance on Steam (Psychological Horror, Atmospheric, Horror, Story Rich, and 2D): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Psychological Horror · Horror · Atmospheric

Still Wakes the Deep
Shared: Psychological Horror · Horror · Story Rich

OMORI
Shared: Psychological Horror · Story Rich · Horror

Mouthwashing
Shared: Psychological Horror · Horror · Atmospheric

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

Layers of Fear (2016)
Shared: Psychological Horror · Horror · Atmospheric

Tiny Bunny
Shared: Horror · Atmospheric · Story Rich

Darkwood
Shared: Horror · Psychological Horror · Atmospheric

What Remains of Edith Finch
Shared: Atmospheric · Story Rich · Walking Simulator

Amnesia: A Machine For Pigs
Shared: Horror · Atmospheric · Story Rich

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

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

Dagon: by H. P. Lovecraft
Shared: Horror · Atmospheric · Psychological Horror

Little Nightmares II
Shared: Horror · Atmospheric · Psychological Horror

Little Nightmares
Shared: Atmospheric · Horror · Story Rich

DISTRAINT: Deluxe Edition
Shared: Psychological Horror · Horror · 2D

Fran Bow
Shared: Psychological Horror · Story Rich · Horror

Firewatch
Shared: Atmospheric · Story Rich · Walking Simulator

MiSide
Shared: Psychological Horror · Story Rich · Horror

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

Mad Father
Shared: Psychological Horror · Horror · 2D

FAITH: The Unholy Trinity
Shared: Psychological Horror · Horror · Story Rich

A Plague Tale: Innocence
Shared: Story Rich · Atmospheric · Medieval

Detention
Shared: Psychological Horror · Horror · Atmospheric