Games like The Slaughter: Act One
Games like The Slaughter: Act One include Return of the Obra Dinn, Murdered: Soul Suspect, The Rewinder, L.A. Noire, and Kathy Rain. We matched them by the tags players give The Slaughter: Act One on Steam (Mystery, Noir, Detective, Dark Humor, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Return of the Obra Dinn
Shared: Mystery · Detective · Atmospheric

Murdered: Soul Suspect
Shared: Mystery · Detective · Adventure

The Rewinder
Shared: Mystery · Adventure · Detective

L.A. Noire
Shared: Detective · Noir · Mystery

Kathy Rain
Shared: Mystery · Adventure · Detective

Danganronpa V3: Killing Harmony
Shared: Detective · Mystery · Dark Humor

Sherlock Holmes: Crimes and Punishments
Shared: Mystery · Detective · Adventure

The Blackwell Legacy
Shared: Mystery · Adventure · Detective

The Room
Shared: Mystery · Atmospheric · Adventure

The Darkside Detective
Shared: Detective · Mystery · Adventure

NORCO
Shared: Mystery · Atmospheric · Noir

What Remains of Edith Finch
Shared: Mystery · Atmospheric · Adventure

Strange Horticulture
Shared: Mystery · Detective · Atmospheric

The Case of the Golden Idol
Shared: Mystery · Detective · Atmospheric

The Séance of Blake Manor
Shared: Detective · Mystery · Atmospheric

Firewatch
Shared: Mystery · Atmospheric · Adventure

The Room Three
Shared: Mystery · Adventure · Atmospheric

Sherlock Holmes: The Devil's Daughter
Shared: Detective · Mystery · Adventure

The Room Two
Shared: Mystery · Atmospheric · Adventure

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

Unavowed
Shared: Adventure · Mystery · Pixel Graphics

The Wolf Among Us
Shared: Detective · Adventure · Noir

The Roottrees are Dead
Shared: Mystery · Detective · Atmospheric

The Excavation of Hob's Barrow
Shared: Adventure · Pixel Graphics · Atmospheric