Games like Within
Games like Within include What Remains of Edith Finch, Firewatch, The Room, Riven, and The House of Da Vinci. We matched them by the tags players give Within on Steam (First-Person, Walking Simulator, Puzzle, Singleplayer, and 3D): closest matches first, and among equally close ones the better-known games.

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

Firewatch
Shared: Walking Simulator · First-Person · Singleplayer

The Room
Shared: Puzzle · Singleplayer · Mystery

Riven
Shared: Puzzle · First-Person · Singleplayer

The House of Da Vinci
Shared: Puzzle · Hidden Object · Singleplayer

Poppy Playtime
Shared: Singleplayer · First-Person · Puzzle

The Witness
Shared: First-Person · Puzzle · Singleplayer

Return of the Obra Dinn
Shared: Puzzle · Singleplayer · Mystery

Quern - Undying Thoughts
Shared: Puzzle · Walking Simulator · First-Person

The Room Two
Shared: Puzzle · Mystery · Hidden Object

The Room Three
Shared: Puzzle · Mystery · Singleplayer

The Room 4: Old Sins
Shared: Puzzle · Mystery · Singleplayer

Blue Prince
Shared: Puzzle · First-Person · Singleplayer

Garten of Banban
Shared: First-Person · Singleplayer · Puzzle

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

The Vanishing of Ethan Carter
Shared: Walking Simulator · First-Person · Mystery

INFRA
Shared: Puzzle · First-Person · Walking Simulator

Outer Wilds
Shared: Puzzle · Mystery · Singleplayer

Garten of Banban 2
Shared: First-Person · Singleplayer · Puzzle

The Looker
Shared: Puzzle · First-Person · Walking Simulator

The Painscreek Killings
Shared: Puzzle · Mystery · Walking Simulator

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

Bendy and the Ink Machine
Shared: First-Person · Puzzle · Singleplayer

The Talos Principle
Shared: First-Person · Puzzle · Singleplayer