Games like Astrophobia
Games like Astrophobia include SOMA, Mouthwashing, Firewatch, FAITH: The Unholy Trinity, and DREDGE. We matched them by the tags players give Astrophobia on Steam (Horror, Retro, Lovecraftian, Atmospheric, and Exploration): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Horror · Atmospheric · Story Rich

Mouthwashing
Shared: Horror · Retro · Atmospheric

Firewatch
Shared: Atmospheric · Story Rich · Exploration

FAITH: The Unholy Trinity
Shared: Horror · Retro · Atmospheric

DREDGE
Shared: Lovecraftian · Exploration · Atmospheric

Crow Country
Shared: Horror · Exploration · 1990's

Look Outside
Shared: Horror · Lovecraftian · Survival Horror

SILENT HILL 2
Shared: Horror · Atmospheric · Story Rich

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

Lethal Company
Shared: Horror · Exploration · Survival Horror

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

Still Wakes the Deep
Shared: Horror · Lovecraftian · Atmospheric

Layers of Fear (2016)
Shared: Horror · Atmospheric · Story Rich

Outer Wilds
Shared: Exploration · Atmospheric · Story Rich

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

Little Nightmares
Shared: Horror · Atmospheric · Story Rich

Fears to Fathom - Norwood Hitchhike
Shared: Horror · Retro · Atmospheric

Outlast
Shared: Horror · Atmospheric · Survival Horror

Alien: Isolation
Shared: Horror · Atmospheric · Survival Horror

Darkwood
Shared: Horror · Survival Horror · Atmospheric

Amnesia: Rebirth
Shared: Horror · Story Rich · Exploration

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

No one lives under the lighthouse Director's cut
Shared: Horror · Atmospheric · Lovecraftian

SUNLESS SEA
Shared: Lovecraftian · Exploration · Atmospheric