Games like Slumberer's Universe
Games like Slumberer's Universe include OMORI, To the Moon, Finding Paradise, Impostor Factory, and Tales of the Black Forest. We matched them by the tags players give Slumberer's Universe on Steam (Emotional, Psychological Horror, Story Rich, Indie, and JRPG): closest matches first, and among equally close ones the better-known games.

OMORI
Shared: Psychological Horror · Story Rich · Indie

To the Moon
Shared: Story Rich · Emotional · Indie

Finding Paradise
Shared: Emotional · Story Rich · Adventure

Impostor Factory
Shared: Emotional · Story Rich · Adventure

Tales of the Black Forest
Shared: Indie · Story Rich · RPG

Rakuen
Shared: Emotional · Story Rich · JRPG

OneShot
Shared: Story Rich · Indie · Pixel Graphics

Mouthwashing
Shared: Psychological Horror · Story Rich · Indie

DISTRAINT: Deluxe Edition
Shared: Psychological Horror · Indie · Story Rich

Persona 5 Royal
Shared: Story Rich · JRPG · Emotional

Fran Bow
Shared: Psychological Horror · Story Rich · Indie

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

Milk outside a bag of milk outside a bag of milk
Shared: Psychological Horror · Story Rich · Indie

Milk inside a bag of milk inside a bag of milk
Shared: Psychological Horror · Psychological · Emotional

LISA: The Painful
Shared: Psychological Horror · Story Rich · Indie

Ib
Shared: Story Rich · Indie · Psychological Horror

The Cat Lady
Shared: Story Rich · Psychological Horror · Indie

OFF
Shared: Story Rich · Psychological Horror · Indie

Persona 3 Reload
Shared: JRPG · Story Rich · Emotional

Persona 4 Golden
Shared: Story Rich · JRPG · Emotional

NEEDY STREAMER OVERLOAD
Shared: Psychological Horror · Anime · Psychological

DELTARUNE
Shared: Story Rich · Emotional · RPG

MiSide
Shared: Psychological Horror · Story Rich · Indie

Just a To the Moon Series Beach Episode
Shared: Emotional · Story Rich · Adventure