Games like Iron Sky: Invasion
Games like Iron Sky: Invasion include SPORE™ Galactic Adventures, Stellaris, Totally Accurate Battle Simulator, Space Rangers HD: A War Apart, and X Rebirth. We matched them by the tags players give Iron Sky: Invasion on Steam (Simulation, Action, Strategy, Space, and Sci-fi): closest matches first, and among equally close ones the better-known games.

SPORE™ Galactic Adventures
Shared: Simulation · Action · Space

Stellaris
Shared: Strategy · Space · Sci-fi

Totally Accurate Battle Simulator
Shared: Simulation · Strategy · Funny

Space Rangers HD: A War Apart
Shared: Space · Strategy · Simulation

X Rebirth
Shared: Simulation · Action · Space

SPORE™
Shared: Simulation · Space · Action

STAR WARS™ Empire at War - Gold Pack
Shared: Strategy · Space · Sci-fi

Elite Dangerous
Shared: Space · Simulation · Sci-fi

Who's Your Daddy?!
Shared: Simulation · Funny · Strategy

X4: Foundations
Shared: Simulation · Space · Strategy

Goat Simulator
Shared: Simulation · Funny · Comedy

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

Hardspace: Shipbreaker
Shared: Simulation · Space · Sci-fi

Shieldwall
Shared: Simulation · Action · Strategy

Kerbal Space Program
Shared: Simulation · Space · Funny

Space Pirates And Zombies 2
Shared: Action · Strategy · Space

ENDLESS Space™ 2
Shared: Strategy · Space · Sci-fi

X3: Terran Conflict
Shared: Simulation · Space · Strategy

STAR WARS™: Squadrons
Shared: Space · Action · Simulation

Homeworld Remastered Collection
Shared: Strategy · Space · Sci-fi

Between the Stars
Shared: Action · Simulation · Space

Ultimate Epic Battle Simulator
Shared: Simulation · Strategy · Action

Spacebase DF-9
Shared: Simulation · Space · Strategy

Dyson Sphere Program
Shared: Space · Simulation · Sci-fi