Games like Signal Intentions
Games like Signal Intentions include Firewatch, Layers of Fear (2016), Outlast, MiSide, and What Remains of Edith Finch. We matched them by the tags players give Signal Intentions on Steam (Adventure, Walking Simulator, Hidden Object, 3D, and First-Person): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Adventure · Walking Simulator · Atmospheric

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

Outlast
Shared: First-Person · Horror · Atmospheric

MiSide
Shared: Psychological Horror · First-Person · Horror

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

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

The Cabin Factory
Shared: Walking Simulator · Horror · Adventure

SOMA
Shared: Horror · Atmospheric · Psychological Horror

ROUTINE
Shared: Adventure · Atmospheric · Sci-fi

Still Wakes the Deep
Shared: Walking Simulator · Horror · First-Person

KARMA: The Dark World
Shared: Walking Simulator · First-Person · Horror

Blair Witch
Shared: Adventure · Horror · First-Person

Scanner Sombre
Shared: Walking Simulator · Adventure · Atmospheric

Welcome to Kowloon
Shared: Adventure · Walking Simulator · Atmospheric

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

Garten of Banban
Shared: First-Person · Horror · 3D

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

Iron Lung
Shared: Atmospheric · Horror · Psychological Horror

From The Darkness
Shared: Horror · Walking Simulator · First-Person

Among the Sleep - Enhanced Edition
Shared: Adventure · Horror · Atmospheric

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

The Room Two
Shared: Hidden Object · Adventure · Atmospheric

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

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Shared: Atmospheric · Horror · Walking Simulator