Games like The Space Between
Games like The Space Between include What Remains of Edith Finch, Firewatch, The Beginner's Guide, Mouthwashing, and Layers of Fear (2016). We matched them by the tags players give The Space Between on Steam (Walking Simulator, Visual Novel, Experimental, Surreal, and Mystery): closest matches first, and among equally close ones the better-known games.

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

Firewatch
Shared: Walking Simulator · Adventure · Atmospheric

The Beginner's Guide
Shared: Walking Simulator · Atmospheric · Surreal

Mouthwashing
Shared: Walking Simulator · Atmospheric · Horror

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

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

CARIMARA: Beneath the forlorn limbs
Shared: Mystery · Adventure · Walking Simulator

Milk inside a bag of milk inside a bag of milk
Shared: Visual Novel · Experimental · Horror

Dagon: by H. P. Lovecraft
Shared: Visual Novel · Atmospheric · Horror

Raging Loop
Shared: Visual Novel · Mystery · Adventure

No one lives under the lighthouse Director's cut
Shared: Adventure · Atmospheric · Horror

The Vanishing of Ethan Carter
Shared: Walking Simulator · Mystery · Atmospheric

The Suicide of Rachel Foster
Shared: Walking Simulator · Mystery · Adventure

RATSHAKER™
Shared: Surreal · Horror · Mystery

Outer Wilds
Shared: Mystery · Adventure · Atmospheric

Higurashi When They Cry Hou - Ch.1 Onikakushi
Shared: Visual Novel · Mystery · Atmospheric

SOMA
Shared: Atmospheric · Horror · Dark

Hellblade: Senua's Sacrifice
Shared: Atmospheric · Adventure · Dark

The Mortuary Assistant
Shared: Mystery · Horror · Surreal

Gone Home
Shared: Walking Simulator · Atmospheric · Adventure

INDIKA
Shared: Surreal · Horror · Dark

Psalm 5:9-13
Shared: Walking Simulator · Mystery · Horror

Poppy Playtime
Shared: Horror · Mystery · Dark

Sally Face - Episode One
Shared: Adventure · Mystery · Dark