Games like 9 Souls
Games like 9 Souls include Poppy Playtime, Layers of Fear (2016), Little Nightmares II, Garten of Banban, and Little Nightmares. We matched them by the tags players give 9 Souls on Steam (Psychological Horror, Horror, Walking Simulator, Casual, and Puzzle): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Puzzle · Psychological Horror

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

Little Nightmares II
Shared: Horror · Psychological Horror · Puzzle

Garten of Banban
Shared: Horror · Psychological Horror · Puzzle

Little Nightmares
Shared: Horror · Atmospheric · Puzzle

SOMA
Shared: Psychological Horror · Horror · Atmospheric

MiSide
Shared: Psychological Horror · Horror · Atmospheric

Outlast
Shared: Horror · Psychological Horror · Atmospheric

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

The Exit 8
Shared: Walking Simulator · Horror · Puzzle

Garten of Banban 2
Shared: Horror · Psychological Horror · Puzzle

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

The Death | Thần Trùng
Shared: Psychological Horror · Horror · Puzzle

Mouthwashing
Shared: Psychological Horror · Horror · Atmospheric

ROUTINE
Shared: Psychological Horror · Atmospheric · Horror

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

Inside the Backrooms
Shared: Horror · Psychological Horror · Puzzle

What Remains of Edith Finch
Shared: Walking Simulator · Atmospheric · Psychological Horror

Visage
Shared: Psychological Horror · Horror · Dark

Fran Bow
Shared: Psychological Horror · Horror · Puzzle

Scanner Sombre
Shared: Horror · Walking Simulator · Psychological Horror

Scorn
Shared: Horror · Atmospheric · Puzzle

Buckshot Roulette
Shared: Horror · Dark · Psychological Horror

Among the Sleep - Enhanced Edition
Shared: Horror · Atmospheric · Walking Simulator

