Games like Prison Anomaly
Games like Prison Anomaly include Mouthwashing, Poppy Playtime, The Exit 8, SOMA, and Summer of '58. We matched them by the tags players give Prison Anomaly on Steam (Psychological Horror, Walking Simulator, Psychological, Puzzle, and Horror): closest matches first, and among equally close ones the better-known games.

Mouthwashing
Shared: Psychological Horror · Horror · Psychological

Poppy Playtime
Shared: Horror · Puzzle · Psychological Horror

The Exit 8
Shared: Walking Simulator · Puzzle · Psychological Horror

SOMA
Shared: Psychological Horror · Horror · Dark

Summer of '58
Shared: Psychological Horror · Horror · Walking Simulator

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

What Remains of Edith Finch
Shared: Walking Simulator · Mystery · Atmospheric

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

Sally Face - Episode One
Shared: Psychological Horror · Horror · Puzzle

Phasmophobia
Shared: Psychological Horror · Horror · Dark

Little Nightmares II
Shared: Horror · Puzzle · Psychological Horror

Firework
Shared: Horror · Puzzle · Psychological Horror

The Room Two
Shared: Puzzle · Mystery · Horror

The Park®
Shared: Psychological Horror · Walking Simulator · Horror

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

Still Wakes the Deep
Shared: Psychological Horror · Horror · Walking Simulator

Platform 8
Shared: Psychological Horror · Walking Simulator · Puzzle

Inside the Backrooms
Shared: Psychological Horror · Horror · Puzzle

Garten of Banban
Shared: Psychological Horror · Horror · Puzzle

Firewatch
Shared: Walking Simulator · Mystery · Atmospheric

Fran Bow
Shared: Psychological Horror · Puzzle · Horror

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

God's Basement
Shared: Psychological Horror · Walking Simulator · Horror

Layers of Fear 2 (2019)
Shared: Psychological Horror · Walking Simulator · Horror