Games like Mothership Down
Games like Mothership Down include Hardspace: Shipbreaker, Bridge Constructor Portal, People Playground, Poly Bridge, and Zup! S. We matched them by the tags players give Mothership Down on Steam (Physics, Puzzle, Old School, Sci-fi, and Building): closest matches first, and among equally close ones the better-known games.

Hardspace: Shipbreaker
Shared: Physics · Sci-fi · Puzzle

Bridge Constructor Portal
Shared: Puzzle · Physics · Building

People Playground
Shared: Physics · Singleplayer · 2D

Poly Bridge
Shared: Physics · Puzzle · Building

Zup! S
Shared: Puzzle · Physics · Singleplayer

World of Goo
Shared: Puzzle · Physics · Singleplayer

Garry's Mod
Shared: Physics · Building · Singleplayer

Kerbal Space Program
Shared: Physics · Building · Space

Cosmoteer: Starship Architect & Commander
Shared: Sci-fi · Building · Singleplayer

Poly Bridge 2
Shared: Physics · Puzzle · Building

Zuma Deluxe
Shared: Puzzle · 2D · Cute

Space Engineers
Shared: Building · Physics · Space

Baba Is You
Shared: Puzzle · Singleplayer · Cute

Crazy Machines 3
Shared: Puzzle · Physics · Singleplayer

Peggle Deluxe
Shared: Puzzle · Physics · Singleplayer

Portal
Shared: Puzzle · Sci-fi · Physics

Zup!
Shared: Puzzle · Physics · 2D

World of Goo 2
Shared: Physics · Puzzle · Building

Reassembly
Shared: Building · Singleplayer · 2D

Hozy
Shared: Puzzle · Physics · Cute

Zup! 3
Shared: Puzzle · Physics · 2D

Oxygen Not Included
Shared: Building · Singleplayer · 2D

OneShot
Shared: Puzzle · Cute · Pixel Graphics

Defy Gravity Extended
Shared: Puzzle · Singleplayer · 2D