Games like Deep Space Siege
Games like Deep Space Siege include FTL: Faster Than Light, Dome Keeper, Heat Signature, Returnal™, and Brotato. We matched them by the tags players give Deep Space Siege on Steam (Action, Bullet Hell, Roguelike, Top-Down, and Choices Matter): closest matches first, and among equally close ones the better-known games.

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

Dome Keeper
Shared: Action · Roguelike · Sci-fi

Heat Signature
Shared: Action · Space · Top-Down

Returnal™
Shared: Action · Bullet Hell · Roguelike

Brotato
Shared: Roguelike · Bullet Hell · Singleplayer

BALL x PIT
Shared: Action · Bullet Hell · Roguelike

Mass Effect™ Legendary Edition
Shared: Choices Matter · Action · Sci-fi

Enter the Gungeon
Shared: Bullet Hell · Roguelike · Action

Megabonk
Shared: Roguelike · Bullet Hell · Action

Vampire Survivors
Shared: Bullet Hell · Roguelike · Action

Noobs Want to Live
Shared: Bullet Hell · Roguelike · Action

STAR WARS™ Battlefront™ II
Shared: Action · Space · Sci-fi

The Binding of Isaac
Shared: Roguelike · Action · Top-Down

Nuclear Throne
Shared: Roguelike · Bullet Hell · Action

Halls of Torment
Shared: Bullet Hell · Roguelike · Action

STAR WARS Jedi: Survivor™
Shared: Action · Singleplayer · Sci-fi

Space Pirates and Zombies
Shared: Action · Space · Top-Down

EVERSPACE™
Shared: Action · Space · Sci-fi

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

Marvel's Guardians of the Galaxy
Shared: Action · Choices Matter · Singleplayer

Atomicrops
Shared: Action · Bullet Hell · Roguelike

Deep Rock Galactic: Survivor
Shared: Bullet Hell · Top-Down · Action

Chorus
Shared: Action · Space · Spaceships

Skul: The Hero Slayer
Shared: Action · Roguelike · Indie