Games like Nightmare
Games like Nightmare include SchoolBoy Runaway, Platform 8, The Room 4: Old Sins, Outer Wilds, and Poppy Playtime. We matched them by the tags players give Nightmare on Steam (Adventure, Simulation, Puzzle, Hidden Object, and Exploration): closest matches first, and among equally close ones the better-known games.
SchoolBoy Runaway
Shared: Adventure · Puzzle · Simulation
Platform 8
Shared: Adventure · Simulation · Puzzle
The Room 4: Old Sins
Shared: Puzzle · Adventure · Mystery
Outer Wilds
Shared: Adventure · Exploration · Puzzle
Poppy Playtime
Shared: Puzzle · First-Person · Adventure
Inside the Backrooms
Shared: Puzzle · Adventure · Exploration
Five Nights at Freddy's: Security Breach
Shared: First-Person · Adventure · Exploration
Blue Prince
Shared: Puzzle · Exploration · Mystery
The House of Da Vinci
Shared: Puzzle · Hidden Object · Adventure
The Room
Shared: Puzzle · Adventure · Hidden Object
The Room Two
Shared: Puzzle · Adventure · Hidden Object
Dread Flats
Shared: Adventure · Puzzle · Thriller
The Room Three
Shared: Adventure · Puzzle · Mystery
Metel - Horror Escape
Shared: Puzzle · Hidden Object · 3D
The Exit 8
Shared: Puzzle · Exploration · First-Person
Amnesia: The Dark Descent
Shared: Puzzle · Adventure · First-Person
Amnesia: Rebirth
Shared: Puzzle · Adventure · First-Person
Eyes: The Horror Game
Shared: Adventure · Exploration · Puzzle
Firewatch
Shared: Adventure · First-Person · Exploration
PEAK
Shared: Adventure · Exploration · First-Person
Escape the Backrooms
Shared: Adventure · First-Person · Exploration
Five Nights at Freddy's: Secret of the Mimic
Shared: Adventure · First-Person · Exploration
MOLE
Shared: Simulation · Adventure · Puzzle
What Remains of Edith Finch
Shared: Adventure · Exploration · First-Person