Games like Complex 629
Games like Complex 629 include SOMA, Layers of Fear (2016), Mouthwashing, Still Wakes the Deep, and Eclipsium. We matched them by the tags players give Complex 629 on Steam (Psychological Horror, Walking Simulator, Surreal, Stylized, and Abstract): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Psychological Horror · Atmospheric · Horror

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

Mouthwashing
Shared: Psychological Horror · Atmospheric · Walking Simulator

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

Eclipsium
Shared: Walking Simulator · Psychological Horror · Surreal

POOLS
Shared: Psychological Horror · Walking Simulator · Atmospheric

Endacopia
Shared: Psychological Horror · Surreal · Horror

DREDGE
Shared: Exploration · Psychological Horror · Atmospheric

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

OMORI
Shared: Psychological Horror · Horror · Atmospheric

Bad Parenting 1: Mr. Red Face
Shared: Psychological Horror · Walking Simulator · Horror

Visage
Shared: Psychological Horror · Dark · Horror

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

Outlast
Shared: Psychological Horror · Atmospheric · Horror

Darkwood
Shared: Psychological Horror · Horror · Atmospheric

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

Mundaun
Shared: Walking Simulator · Psychological Horror · Stylized

Firewatch
Shared: Walking Simulator · Atmospheric · Exploration

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

DISTRAINT 2
Shared: Psychological Horror · Atmospheric · Walking Simulator

Little Nightmares II
Shared: Psychological Horror · Atmospheric · Horror

ROUTINE
Shared: Psychological Horror · Atmospheric · Dark

NaissanceE
Shared: Walking Simulator · Exploration · Abstract

THRESHOLD
Shared: Psychological Horror · Walking Simulator · Atmospheric