Games like The Twin Paradox
Games like The Twin Paradox include Undertale, OMORI, OneShot, Mass Effect™ Legendary Edition, and Kerbal Space Program. We matched them by the tags players give The Twin Paradox on Steam (RPG, Pixel Graphics, Science, Multiple Endings, and Space): closest matches first, and among equally close ones the better-known games.

Undertale
Shared: Pixel Graphics · Multiple Endings · RPG

OMORI
Shared: Pixel Graphics · RPG · Multiple Endings

OneShot
Shared: Pixel Graphics · Story Rich · Multiple Endings

Mass Effect™ Legendary Edition
Shared: RPG · Space · Sci-fi

Kerbal Space Program
Shared: Space · Science · Physics

Starfield
Shared: RPG · Space · Sci-fi

Back to the Dawn
Shared: RPG · Pixel Graphics · Multiple Endings

DELTARUNE
Shared: Pixel Graphics · RPG · Story Rich

STAR WARS™ Knights of the Old Republic™ II - The Sith Lords™
Shared: RPG · Sci-fi · Choices Matter

Drova - Forsaken Kin
Shared: RPG · Pixel Graphics · 2D

Aliya: Timelink
Shared: RPG · Multiple Endings · Space

STAR WARS™ Knights of the Old Republic™
Shared: RPG · Sci-fi · Story Rich

Yes, Your Grace
Shared: Pixel Graphics · RPG · Choices Matter

Martial Law
Shared: Pixel Graphics · Multiple Endings · Choices Matter

Mass Effect (2007)
Shared: RPG · Sci-fi · Space

Baldur's Gate 3
Shared: RPG · Choices Matter · Story Rich

Endless Sky
Shared: Space · RPG · Sci-fi

Ten Trials of Babel: The Doppelganger Maze
Shared: Pixel Graphics · Multiple Endings · RPG

CrossCode
Shared: Pixel Graphics · RPG · 2D

Detroit: Become Human
Shared: Multiple Endings · Choices Matter · Story Rich

The Witcher 3: Wild Hunt — Remastered
Shared: RPG · Story Rich · Choices Matter

Ib
Shared: Pixel Graphics · RPG · 2D

Legend of Mortal
Shared: RPG · Multiple Endings · Choices Matter

Disco Elysium - The Final Cut
Shared: RPG · Choices Matter · Story Rich