Games like Alteratio
Games like Alteratio include MiSide, Little Nightmares II, Poppy Playtime, Five Nights at Freddy's: Security Breach, and Escape the Backrooms. We matched them by the tags players give Alteratio on Steam (Adventure, Horror, Thriller, Psychological Horror, and Puzzle): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Psychological Horror · Horror · Story Rich

Little Nightmares II
Shared: Adventure · Horror · Puzzle

Poppy Playtime
Shared: Horror · Puzzle · Psychological Horror

Five Nights at Freddy's: Security Breach
Shared: Horror · Adventure · Stealth

Escape the Backrooms
Shared: Horror · Psychological Horror · Adventure

Little Nightmares
Shared: Horror · Adventure · Puzzle

Amnesia: Rebirth
Shared: Puzzle · Horror · Adventure

Bendy and the Dark Revival
Shared: Horror · Adventure · First-Person

Hello Neighbor 2
Shared: Adventure · Horror · Puzzle

Hello Neighbor
Shared: Horror · Stealth · First-Person

Paper Dolls: Original /
Shared: Adventure · Horror · Thriller

Outlast
Shared: Horror · Psychological Horror · First-Person

Penumbra: Black Plague Gold Edition
Shared: Adventure · Horror · Psychological Horror

Garten of Banban
Shared: Horror · Psychological Horror · Puzzle

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

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

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

Alan Wake
Shared: Horror · Adventure · Thriller

Penumbra Overture
Shared: Adventure · Horror · Psychological Horror

Fran Bow
Shared: Psychological Horror · Horror · Adventure

Inside the Backrooms
Shared: Horror · Psychological Horror · Puzzle

Superliminal
Shared: Puzzle · Thriller · First-Person

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

Detention
Shared: Horror · Psychological Horror · Adventure