Games like Casting Whispers
Games like Casting Whispers include SOMA, Sally Face - Episode One, What Remains of Edith Finch, Phasmophobia, and Dagon: by H. P. Lovecraft. We matched them by the tags players give Casting Whispers on Steam (Psychological Horror, Atmospheric, Lovecraftian, Investigation, and Story Rich): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Psychological Horror · Atmospheric · Horror

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

What Remains of Edith Finch
Shared: Atmospheric · Story Rich · Mystery

Phasmophobia
Shared: Psychological Horror · Horror · Investigation

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

Still Wakes the Deep
Shared: Psychological Horror · Lovecraftian · Horror

Mouthwashing
Shared: Psychological Horror · Atmospheric · Story Rich

MiSide
Shared: Psychological Horror · Story Rich · Horror

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

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

Little Nightmares
Shared: Atmospheric · Horror · Psychological Horror

Little Nightmares II
Shared: Horror · Atmospheric · Psychological Horror

Oxenfree
Shared: Atmospheric · Story Rich · Female Protagonist

Call of Cthulhu®
Shared: Psychological Horror · Lovecraftian · Atmospheric

Fran Bow
Shared: Psychological Horror · Story Rich · Horror

Hellblade: Senua's Sacrifice
Shared: Atmospheric · Story Rich · Female Protagonist

Outlast
Shared: Atmospheric · Psychological Horror · Horror

SIGNALIS
Shared: Psychological Horror · Atmospheric · Lovecraftian

Poppy Playtime
Shared: Horror · Psychological Horror · Dark

Firewatch
Shared: Atmospheric · Story Rich · Adventure

Amnesia: A Machine For Pigs
Shared: Atmospheric · Psychological Horror · Horror

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

The Medium
Shared: Psychological Horror · Atmospheric · Horror

Detention
Shared: Psychological Horror · Atmospheric · Horror