Games like Hallway 41
Games like Hallway 41 include Firewatch, What Remains of Edith Finch, The Witness, Layers of Fear (2016), and The Exit 8. We matched them by the tags players give Hallway 41 on Steam (Walking Simulator, Casual, First-Person, Psychological Horror, and Singleplayer): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Walking Simulator · Adventure · First-Person

What Remains of Edith Finch
Shared: Walking Simulator · First-Person · Adventure

The Witness
Shared: First-Person · Puzzle · Singleplayer

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

The Exit 8
Shared: Walking Simulator · Psychological Horror · Puzzle

The Stanley Parable
Shared: Walking Simulator · First-Person · Indie

Slime Rancher
Shared: Singleplayer · First-Person · Adventure

Poppy Playtime
Shared: Singleplayer · First-Person · Psychological Horror

Fears to Fathom - Woodbury Getaway
Shared: Psychological Horror · First-Person · Casual

The Death | Thần Trùng
Shared: Psychological Horror · Casual · Adventure

BABBDI
Shared: Walking Simulator · First-Person · Casual

Scanner Sombre
Shared: Walking Simulator · First-Person · Adventure

INFRA
Shared: Walking Simulator · First-Person · Puzzle

Riven
Shared: First-Person · Adventure · Puzzle

The Beginner's Guide
Shared: Walking Simulator · First-Person · Indie

Fears to Fathom® - Scratch Creek
Shared: Psychological Horror · Casual · Walking Simulator

Call of the Sea
Shared: First-Person · Adventure · Puzzle

POOLS
Shared: Walking Simulator · Psychological Horror · First-Person

Blue Prince
Shared: Puzzle · Singleplayer · First-Person

ROUTINE
Shared: Psychological Horror · Singleplayer · Adventure

Amnesia: A Machine For Pigs
Shared: Walking Simulator · First-Person · Psychological Horror

Obduction
Shared: Adventure · First-Person · Puzzle

The Moon Sliver
Shared: Walking Simulator · Psychological Horror · First-Person

Antichamber
Shared: First-Person · Puzzle · Indie