Games like Otherside
Games like Otherside include Stray, Outer Wilds, Little Nightmares, SOMA, and Little Nightmares II. We matched them by the tags players give Otherside on Steam (Sci-fi, Adventure, Casual, Horror, and Psychedelic): closest matches first, and among equally close ones the better-known games.

Stray
Shared: Adventure · Atmospheric · Puzzle

Outer Wilds
Shared: Adventure · Atmospheric · Exploration

Little Nightmares
Shared: Adventure · Horror · Atmospheric

SOMA
Shared: Horror · Sci-fi · Atmospheric

Little Nightmares II
Shared: Adventure · Horror · Atmospheric

The Room
Shared: Adventure · Puzzle · Atmospheric

ROUTINE
Shared: Sci-fi · Adventure · Atmospheric

Moncage
Shared: Casual · Adventure · Puzzle

Observation
Shared: Adventure · Sci-fi · Horror

Deliver Us The Moon
Shared: Adventure · Sci-fi · Indie

LIMBO
Shared: Adventure · Puzzle · Indie

The Talos Principle
Shared: Sci-fi · Puzzle · Atmospheric

Firewatch
Shared: Adventure · Atmospheric · Horror

MOLE
Shared: Adventure · Horror · Simulation

Iron Lung
Shared: Horror · Atmospheric · Indie

Layers of Fear (2016)
Shared: Horror · Atmospheric · Adventure

Lethal Company
Shared: Horror · Sci-fi · Atmospheric

Antichamber
Shared: Puzzle · Adventure · Indie

Iris.Fall
Shared: Adventure · Casual · Horror

INSIDE
Shared: Horror · Atmospheric · Adventure

The Room Two
Shared: Adventure · Puzzle · Horror

Subnautica
Shared: Horror · Adventure · Sci-fi

[Chillas Art] The Convenience Store
Shared: Horror · Adventure · Casual

FAR: Lone Sails
Shared: Adventure · Atmospheric · Puzzle