Games like Spacetime Shooter
Games like Spacetime Shooter include Portal, Samsara Room, Baba Is You, Zup! S, and LIMBO. We matched them by the tags players give Spacetime Shooter on Steam (Puzzle, Sniper, Top-Down Shooter, 2D, and Top-Down): closest matches first, and among equally close ones the better-known games.

Portal
Shared: Puzzle · Sci-fi · Singleplayer

Samsara Room
Shared: Puzzle · Free to Play · Singleplayer

Baba Is You
Shared: Puzzle · Singleplayer · 2D

Zup! S
Shared: Puzzle · 2D · Singleplayer

LIMBO
Shared: Puzzle · 2D · Singleplayer

Poppy Playtime
Shared: Puzzle · Singleplayer · Free to Play

Door Kickers
Shared: Top-Down · Tactical · 2D

Snake Force
Shared: Top-Down Shooter · Free to Play · Top-Down

World of Goo
Shared: Puzzle · 2D · Singleplayer

Intravenous
Shared: Top-Down Shooter · Top-Down · Tactical

Bridge Constructor Portal
Shared: Puzzle · 2D · Singleplayer

Firework
Shared: Puzzle · 2D · Singleplayer

Endless Sky
Shared: Sci-fi · Free to Play · 2D

Defy Gravity Extended
Shared: Puzzle · 2D · Singleplayer

FTL: Faster Than Light
Shared: Sci-fi · Singleplayer · Top-Down

The Mr. Rabbit Magic Show
Shared: Puzzle · Free to Play · 2D

BEEP
Shared: 2D · Puzzle · Singleplayer

Portal 2
Shared: Puzzle · Singleplayer · Sci-fi

Zup!
Shared: Puzzle · 2D · Indie

The Bridge
Shared: Puzzle · 2D · Singleplayer

The Swapper
Shared: Puzzle · Sci-fi · Singleplayer

Gunpoint
Shared: Puzzle · 2D · Singleplayer

Zup! 2
Shared: Puzzle · 2D · Indie

Superliminal
Shared: Puzzle · Singleplayer · Surreal