Games like Unhuman Nightmare
Games like Unhuman Nightmare include Lethal Company, Phasmophobia, R.E.P.O., Escape the Backrooms, and Dying Light. We matched them by the tags players give Unhuman Nightmare on Steam (Online Co-Op, Horror, First-Person, PvE, and Survival): closest matches first, and among equally close ones the better-known games.

Lethal Company
Shared: Online Co-Op · Horror · First-Person

Phasmophobia
Shared: Online Co-Op · Horror · Co-op

R.E.P.O.
Shared: Online Co-Op · Horror · Co-op

Escape the Backrooms
Shared: Horror · Online Co-Op · Co-op

Dying Light
Shared: Horror · Online Co-Op · First-Person

Dead by Daylight
Shared: Horror · Online Co-Op · Co-op

Left 4 Dead 2
Shared: Co-op · Online Co-Op · Horror

The Outlast Trials
Shared: Horror · Co-op · First-Person

Pacify
Shared: Online Co-Op · Horror · Co-op

Zort
Shared: Online Co-Op · Horror · Co-op

KLETKA
Shared: Horror · Online Co-Op · Co-op

PEAK
Shared: Online Co-Op · Co-op · First-Person

Sons Of The Forest
Shared: Survival · Co-op · Horror

The Forest
Shared: Horror · Survival · First-Person

How to Fish
Shared: Online Co-Op · Co-op · First-Person

PUBG: BATTLEGROUNDS
Shared: Survival · Online Co-Op · Action

Backrooms: Escape Together
Shared: Horror · Online Co-Op · Co-op

DEVOUR
Shared: Online Co-Op · Horror · Co-op

PANICORE
Shared: Online Co-Op · Horror · Co-op

Demonologist
Shared: Horror · Online Co-Op · Co-op

MISERY
Shared: Online Co-Op · Horror · Survival

Nuclear Nightmare
Shared: Online Co-Op · Horror · Co-op

No More Room in Hell 2
Shared: Online Co-Op · Co-op · Survival

Back 4 Blood
Shared: Online Co-Op · Co-op · Horror