Games like Simulation 9
Games like Simulation 9 include The Exit 8, Killer Frequency, Scanner Sombre, Firewatch, and Platform 8. We matched them by the tags players give Simulation 9 on Steam (Adventure, Puzzle, Simulation, Casual, and Walking Simulator): closest matches first, and among equally close ones the better-known games.

The Exit 8
Shared: Puzzle · Exploration · Walking Simulator

Killer Frequency
Shared: Adventure · Puzzle · Horror

Scanner Sombre
Shared: Adventure · Walking Simulator · Exploration

Firewatch
Shared: Adventure · Walking Simulator · Atmospheric

Platform 8
Shared: Adventure · Simulation · Puzzle

Riven
Shared: Adventure · Puzzle · Exploration

The Cabin Factory
Shared: Walking Simulator · Horror · Adventure

Spirit of the North
Shared: Adventure · Puzzle · Casual

Big Walk
Shared: Puzzle · Adventure · Exploration

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

INFRA
Shared: Puzzle · Adventure · Exploration

Outer Wilds
Shared: Adventure · Exploration · Puzzle

Stray
Shared: Adventure · Puzzle · Exploration

The Witness
Shared: Puzzle · Exploration · Adventure

MOLE
Shared: Adventure · Simulation · Puzzle

Slime Rancher
Shared: Adventure · Exploration · Simulation

The Death | Thần Trùng
Shared: Puzzle · Adventure · Horror

The Room
Shared: Puzzle · Adventure · Atmospheric

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

The Forest
Shared: Adventure · Horror · Exploration

Internet Cafe Simulator 2
Shared: Simulation · Exploration · Adventure

[Chillas Art] The Closing Shift
Shared: Adventure · Simulation · Casual

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