Games like Hallucinations
Games like Hallucinations include MiSide, Outlast, Poppy Playtime, Resident Evil 7 Biohazard, and Firewatch. We matched them by the tags players give Hallucinations on Steam (3D, First-Person, Adventure, Psychological Horror, and Horror): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Psychological Horror · First-Person · 3D

Outlast
Shared: First-Person · Horror · Psychological Horror

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

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

Firewatch
Shared: Adventure · First-Person · Atmospheric

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

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

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

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

Resident Evil Village
Shared: First-Person · Horror · Zombies

Subliminal
Shared: Psychological Horror · First-Person · Horror

Phasmophobia
Shared: Horror · Psychological Horror · First-Person

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

Mouthwashing
Shared: Psychological Horror · Horror · Atmospheric

Psalm 5:9-13
Shared: Psychological Horror · Horror · First-Person

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

Welcome to Kowloon
Shared: Horror · Adventure · Psychological Horror

SOMA
Shared: Psychological Horror · Horror · Atmospheric

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

Five Nights at Freddy's: Security Breach
Shared: Horror · First-Person · 3D

Inside the Backrooms
Shared: Horror · Psychological Horror · Adventure

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

Garten of Banban 2
Shared: First-Person · Horror · Psychological Horror

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