Games like Doorways: Old Prototype
Games like Doorways: Old Prototype include Poppy Playtime, Outlast, Dark Deception, Ultimate Custom Night, and A Story About My Uncle. We matched them by the tags players give Doorways: Old Prototype on Steam (Free to Play, Horror, Adventure, Action, and Parkour): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Free to Play · First-Person

Outlast
Shared: Horror · First-Person · Adventure

Dark Deception
Shared: Free to Play · Horror · First-Person

Ultimate Custom Night
Shared: Free to Play · Horror · Singleplayer

A Story About My Uncle
Shared: Adventure · Parkour · First-Person

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

Firewatch
Shared: Adventure · First-Person · Atmospheric

Valley
Shared: Adventure · First-Person · Parkour

Layers of Fear (2016)
Shared: Horror · First-Person · Adventure

Little Nightmares
Shared: Horror · Adventure · Singleplayer

Little Nightmares II
Shared: Horror · Adventure · Singleplayer

We Were Here
Shared: Free to Play · Horror · Adventure

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

Resident Evil 7 Biohazard
Shared: Horror · First-Person · Singleplayer

Bendy and the Dark Revival
Shared: Horror · Action · Adventure

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

White Knuckle
Shared: Horror · Parkour · First-Person

Spooky's Jump Scare Mansion: HD Renovation
Shared: Horror · Adventure · Indie

Halo Infinite
Shared: Free to Play · Action · First-Person

Garten of Banban
Shared: Horror · First-Person · Singleplayer

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

The Forest
Shared: Horror · Adventure · Action

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

Samsara Room
Shared: Free to Play · Adventure · Indie