Games like Lonely Astronaut
Games like Lonely Astronaut include Goat Simulator, Kerbal Space Program, Timberman, Gang Beasts, and Defy Gravity Extended. We matched them by the tags players give Lonely Astronaut on Steam (Casual, Action, Simulation, Indie, and Score Attack): closest matches first, and among equally close ones the better-known games.

Goat Simulator
Shared: Simulation · Casual · Action

Kerbal Space Program
Shared: Simulation · Space · Physics

Timberman
Shared: Casual · Indie · Action

Gang Beasts
Shared: Action · Casual · Physics

Defy Gravity Extended
Shared: Indie · Action · Space

Surgeon Simulator
Shared: Simulation · Indie · Physics

Retrowave
Shared: Casual · Indie · Simulation

Orbt XL
Shared: Action · Arcade · Casual

Universe Sandbox
Shared: Simulation · Space · Casual

Marble Mayhem: Fragile Ball
Shared: Casual · Indie · Action

Superflight
Shared: Casual · Indie · Action

Solar 2
Shared: Casual · Indie · Space

Cyberhunt
Shared: Action · Casual · Indie

Slackers - Carts of Glory
Shared: Casual · Simulation · Indie

Beyond Gravity
Shared: Casual · Action · Indie

Garry's Mod
Shared: Casual · Physics · Simulation

Shower With Your Dad Simulator 2015: Do You Still Shower With Your Dad
Shared: Casual · Arcade · Action

Angels Fall First
Shared: Action · Indie · Simulation

Super Hexagon
Shared: Indie · Arcade · Action

Mountain
Shared: Casual · Simulation · Indie

Deliver Us The Moon
Shared: Action · Indie · Space

FTL: Faster Than Light
Shared: Space · Indie · Sci-fi

Passpartout: The Starving Artist
Shared: Casual · Simulation · Indie

SPORE™
Shared: Simulation · Casual · Space