Games like Immortal Defense
Games like Immortal Defense include FTL: Faster Than Light, Outer Wilds, Transistor, Homeworld Remastered Collection, and Deliver Us The Moon. We matched them by the tags players give Immortal Defense on Steam (Indie, Strategy, Action, Tower Defense, and Space): closest matches first, and among equally close ones the better-known games.

FTL: Faster Than Light
Shared: Strategy · Indie · Space

Outer Wilds
Shared: Space · Story Rich · Great Soundtrack

Transistor
Shared: Indie · Great Soundtrack · Sci-fi

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

Deliver Us The Moon
Shared: Indie · Action · Space

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

Homeworld: Deserts of Kharak
Shared: Strategy · Sci-fi · Space

Space Run
Shared: Strategy · Indie · Tower Defense

Hollow Knight
Shared: Indie · Great Soundtrack · Difficult

Hollow Knight: Silksong
Shared: Indie · Great Soundtrack · Difficult

X-Morph: Defense
Shared: Strategy · Indie · Tower Defense

Hotline Miami
Shared: Indie · Action · Great Soundtrack

Sanctum 2
Shared: Tower Defense · Strategy · Action

Black Mesa
Shared: Action · Sci-fi · Atmospheric

GemCraft - Chasing Shadows
Shared: Strategy · Indie · Tower Defense

Half-Life 2
Shared: Action · Sci-fi · Story Rich

Katana ZERO
Shared: Action · Indie · Great Soundtrack

Hades
Shared: Indie · Action · Great Soundtrack

Halo: The Master Chief Collection
Shared: Great Soundtrack · Sci-fi · Story Rich

Orcs Must Die!
Shared: Strategy · Action · Tower Defense

Rock 'N' Roll Defense
Shared: Strategy · Tower Defense · Action

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

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

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