Games like Sycamore End
Games like Sycamore End include MiSide, Firewatch, What Remains of Edith Finch, Outer Wilds, and SOMA. We matched them by the tags players give Sycamore End on Steam (Adventure, Horror, Psychological Horror, Story Rich, and Exploration): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Psychological Horror · Story Rich · Horror

Firewatch
Shared: Adventure · Story Rich · Atmospheric

What Remains of Edith Finch
Shared: Story Rich · Adventure · Atmospheric

Outer Wilds
Shared: Adventure · Exploration · Story Rich

SOMA
Shared: Horror · Psychological Horror · Story Rich

Mouthwashing
Shared: Horror · Psychological Horror · Story Rich

Layers of Fear (2016)
Shared: Horror · Psychological Horror · Adventure

Amnesia: A Machine For Pigs
Shared: Horror · Story Rich · Psychological Horror

Fears to Fathom - Ironbark Lookout
Shared: Horror · Psychological Horror · Adventure

Escape the Backrooms
Shared: Horror · Psychological Horror · Adventure

Sally Face - Episode One
Shared: Psychological Horror · Story Rich · Horror

Inside the Backrooms
Shared: Horror · Psychological Horror · Adventure

Subliminal
Shared: Psychological Horror · Horror · Realistic

Amanda the Adventurer
Shared: Horror · First-Person · Adventure

Lethal Company
Shared: Horror · First-Person · Psychological Horror

Little Nightmares II
Shared: Adventure · Horror · Psychological Horror

Five Nights at Freddy's: Security Breach
Shared: Horror · First-Person · Adventure

The Complex: Expedition
Shared: Horror · Exploration · Psychological Horror

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

Outlast
Shared: Horror · Psychological Horror · First-Person

Little Nightmares
Shared: Horror · Adventure · Atmospheric

Backrooms: Escape Together
Shared: Horror · Psychological Horror · First-Person

SILENT HILL 2
Shared: Horror · Psychological Horror · Story Rich

Still Wakes the Deep
Shared: Horror · Psychological Horror · Story Rich

