Games like A Last will and Testament: Adventure
Games like A Last will and Testament: Adventure include Firewatch, What Remains of Edith Finch, The Room, Slime Rancher, and The Room 4: Old Sins. We matched them by the tags players give A Last will and Testament: Adventure on Steam (Adventure, Walking Simulator, First-Person, Casual, and Simulation): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Adventure · Walking Simulator · First-Person

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

The Room
Shared: Adventure · Puzzle · Mystery

Slime Rancher
Shared: Adventure · First-Person · Exploration

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

The Witness
Shared: First-Person · Puzzle · Exploration

Poppy Playtime
Shared: First-Person · Puzzle · Dark

The Room Three
Shared: Adventure · Puzzle · Mystery

The Room Two
Shared: Adventure · Puzzle · Mystery

Escape Simulator
Shared: Adventure · First-Person · Puzzle

Obduction
Shared: Adventure · First-Person · Puzzle

Platform 8
Shared: Adventure · Walking Simulator · Simulation

Riven
Shared: Adventure · First-Person · Puzzle

Amnesia: Rebirth
Shared: First-Person · Adventure · Puzzle

Blue Prince
Shared: Puzzle · First-Person · Exploration

Outer Wilds
Shared: Adventure · Exploration · Mystery

The Exit 8
Shared: Walking Simulator · Puzzle · Exploration

Atomic Heart
Shared: Adventure · Puzzle · First-Person

Strange Horticulture
Shared: Puzzle · Dark · Mystery

Quern - Undying Thoughts
Shared: Adventure · Walking Simulator · Puzzle

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

INFRA
Shared: First-Person · Walking Simulator · Adventure

The Long Dark
Shared: Adventure · First-Person · Exploration

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