Games like The Vessel
Games like The Vessel include MiSide, Iron Lung, Papers, Please, The Test, and Five Nights at Freddy's. We matched them by the tags players give The Vessel on Steam (Simulation, 3D, Pixel Graphics, Atmospheric, and Psychological Horror): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Psychological Horror · 3D · Horror

Iron Lung
Shared: Atmospheric · Horror · Psychological Horror

Papers, Please
Shared: Simulation · Pixel Graphics · Indie

The Test
Shared: Simulation · Pixel Graphics · Psychological Horror

Five Nights at Freddy's
Shared: Horror · Psychological Horror · Singleplayer

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

DISTRAINT: Deluxe Edition
Shared: Pixel Graphics · Psychological Horror · Indie

Lobotomy Corporation | Monster Management Simulation
Shared: Simulation · Psychological Horror · Horror

OMORI
Shared: Psychological Horror · Pixel Graphics · Indie

Kiosk
Shared: Psychological Horror · Horror · Pixel Graphics

Outlast
Shared: Horror · Atmospheric · Psychological Horror

Firework
Shared: Horror · Indie · Psychological Horror

Little Nightmares
Shared: Atmospheric · Horror · Singleplayer

Garten of Banban
Shared: Horror · Psychological Horror · 3D

IMSCARED
Shared: Pixel Graphics · Horror · Psychological Horror

Pony Island
Shared: Pixel Graphics · Psychological Horror · Indie

Mouthwashing
Shared: Psychological Horror · Atmospheric · Horror

Tales of the Black Forest
Shared: Pixel Graphics · Horror · Indie

FAITH: The Unholy Trinity
Shared: Pixel Graphics · Horror · Psychological Horror

Buddy Simulator 1984
Shared: Psychological Horror · Pixel Graphics · Indie

Buckshot Roulette
Shared: Horror · 3D · Indie

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

Little Nightmares II
Shared: Horror · Atmospheric · Singleplayer

KinitoPET
Shared: Psychological Horror · Horror · Indie