Games like Ninehells Ch 2
Games like Ninehells Ch 2 include Outlast, Firewatch, Layers of Fear (2016), What Remains of Edith Finch, and Visage. We matched them by the tags players give Ninehells Ch 2 on Steam (Adventure, Indie, First-Person, Psychological Horror, and Walking Simulator): closest matches first, and among equally close ones the better-known games.

Outlast
Shared: First-Person · Psychological Horror · Horror

Firewatch
Shared: Adventure · Walking Simulator · First-Person

Layers of Fear (2016)
Shared: Psychological Horror · First-Person · Walking Simulator

What Remains of Edith Finch
Shared: First-Person · Walking Simulator · Adventure

Visage
Shared: Psychological Horror · First-Person · Horror

SOMA
Shared: Psychological Horror · Horror · Atmospheric

Slender: The Arrival
Shared: First-Person · Indie · Horror

Poppy Playtime
Shared: First-Person · Horror · Psychological Horror

Amnesia: A Machine For Pigs
Shared: Walking Simulator · First-Person · Horror

Lethal Company
Shared: First-Person · Horror · Psychological Horror

Escape the Backrooms
Shared: Psychological Horror · Horror · First-Person

Scanner Sombre
Shared: Adventure · Walking Simulator · Exploration

Blair Witch
Shared: Adventure · Indie · Psychological Horror

Inside the Backrooms
Shared: Psychological Horror · Adventure · Horror

Among the Sleep - Enhanced Edition
Shared: Indie · Adventure · First-Person

From The Darkness
Shared: Indie · Psychological Horror · First-Person

Outlast 2
Shared: Psychological Horror · First-Person · Horror

Amnesia: The Dark Descent
Shared: Psychological Horror · Horror · First-Person

The Beast Inside
Shared: Adventure · First-Person · Horror

Five Nights at Freddy's
Shared: Indie · Psychological Horror · Horror

Still Wakes the Deep
Shared: Psychological Horror · First-Person · Horror

Backrooms: Escape Together
Shared: Psychological Horror · Horror · First-Person

Little Nightmares
Shared: Adventure · Atmospheric · Horror

ROUTINE
Shared: Psychological Horror · Adventure · Atmospheric

