Games like weekdays
Games like weekdays include Poppy Playtime, SOMA, Outlast, Little Nightmares II, and Little Nightmares. We matched them by the tags players give weekdays on Steam (Horror, First-Person, Dark, Puzzle, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · First-Person · Puzzle

SOMA
Shared: Horror · Atmospheric · Dark

Outlast
Shared: Horror · First-Person · Atmospheric

Little Nightmares II
Shared: Horror · Puzzle · Dark

Little Nightmares
Shared: Horror · Atmospheric · Dark

Amnesia: The Dark Descent
Shared: Horror · First-Person · Atmospheric

Resident Evil 7 Biohazard
Shared: Horror · First-Person · Singleplayer

MiSide
Shared: Horror · First-Person · Psychological Horror

Layers of Fear (2016)
Shared: Horror · First-Person · Atmospheric

Garten of Banban
Shared: Horror · First-Person · Singleplayer

Buckshot Roulette
Shared: Dark · Horror · First-Person

Bendy and the Ink Machine
Shared: Horror · First-Person · Puzzle

Outlast 2
Shared: Horror · First-Person · Psychological Horror

Scorn
Shared: Horror · Atmospheric · First-Person

Sally Face - Episode One
Shared: Horror · Dark · Psychological Horror

Five Nights at Freddy's
Shared: Horror · Singleplayer · First-Person

Inside the Backrooms
Shared: Horror · Puzzle · Psychological Horror

ROUTINE
Shared: Singleplayer · Atmospheric · Dark

MADiSON
Shared: Horror · Dark · First-Person

Garten of Banban 2
Shared: Horror · First-Person · Puzzle

Phasmophobia
Shared: Horror · First-Person · Psychological Horror

Resident Evil Village
Shared: Horror · First-Person · Singleplayer

The Room Two
Shared: Puzzle · Horror · Atmospheric

No, I'm not a Human
Shared: Horror · Psychological Horror · Singleplayer