Games like Descending Horror
Games like Descending Horror include The Exit 8, PEAK, September 7th, Sonic Frontiers, and Five Nights at Freddy's: Security Breach. We matched them by the tags players give Descending Horror on Steam (Exploration, 3D Platformer, Dungeon Crawler, Platformer, and Walking Simulator): closest matches first, and among equally close ones the better-known games.

The Exit 8
Shared: Exploration · Walking Simulator · Horror

PEAK
Shared: Exploration · First-Person · 3D

September 7th
Shared: Exploration · Walking Simulator · 3D Platformer

Sonic Frontiers
Shared: 3D Platformer · Exploration · 3D

Five Nights at Freddy's: Security Breach
Shared: Horror · Exploration · First-Person

PILGRIM
Shared: Exploration · Dungeon Crawler · Horror

Scanner Sombre
Shared: Exploration · Walking Simulator · Horror

Firewatch
Shared: Walking Simulator · Exploration · First-Person

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

Pseudoregalia
Shared: 3D Platformer · Exploration · Platformer

Valley
Shared: Exploration · First-Person · Adventure

Lethal Company
Shared: Exploration · Horror · First-Person

Five Nights at Freddy's: Secret of the Mimic
Shared: Exploration · Horror · First-Person

Fallout 4
Shared: Exploration · Post-apocalyptic · First-Person

R.E.P.O.
Shared: Horror · 3D · First-Person

Portal 2
Shared: Platformer · First-Person · 3D Platformer

Mirror's Edge™
Shared: Exploration · 3D Platformer · First-Person

Content Warning
Shared: Exploration · Horror · First-Person

NaissanceE
Shared: Exploration · Walking Simulator · First-Person

Toree 3D
Shared: 3D Platformer · Platformer · Exploration

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

Amnesia: A Machine For Pigs
Shared: Walking Simulator · Exploration · Horror

The Long Dark
Shared: Exploration · First-Person · Walking Simulator

Hypnagogia² 無限の夢 Boundless Dreams
Shared: Exploration · Platformer · Horror