Games like Through the Galaxy
Games like Through the Galaxy include Vampire Survivors, Skul: The Hero Slayer, Rogue Legacy, Risk of Rain (2013), and Dead Cells. We matched them by the tags players give Through the Galaxy on Steam (Action, Space, Roguelike, Pixel Graphics, and Platformer): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Pixel Graphics · 2D · Roguelike

Skul: The Hero Slayer
Shared: Action · Pixel Graphics · Roguelike

Rogue Legacy
Shared: Roguelike · Action · Platformer

Risk of Rain (2013)
Shared: Roguelike · Action · Platformer

Dead Cells
Shared: Roguelike · Pixel Graphics · 2D

Dungreed
Shared: Roguelike · Pixel Graphics · Action

Rogue Legacy 2
Shared: Action · Platformer · RPG

Death Must Die
Shared: Pixel Graphics · Action · RPG

Halls of Torment
Shared: Pixel Graphics · Roguelike · Action

Noita
Shared: Roguelike · Pixel Graphics · 2D

Hades II
Shared: Action · Roguelike · RPG

Broforce
Shared: Action · Pixel Graphics · 2D

Katana ZERO
Shared: Action · Pixel Graphics · Platformer

BlazBlue Entropy Effect
Shared: Action · 2D · Platformer

Magicite
Shared: Roguelike · Pixel Graphics · RPG

The Binding of Isaac: Rebirth
Shared: Roguelike · Pixel Graphics · 2D

BALL x PIT
Shared: Action · Roguelike · Pixel Graphics

Hades
Shared: Action · Roguelike · Action Roguelike

Downwell
Shared: Pixel Graphics · Action · Platformer

Streets of Rogue
Shared: Pixel Graphics · Action · Roguelike

Megabonk
Shared: Roguelike · Action · Pixel Graphics

Blade Assault
Shared: Action · Roguelike · Pixel Graphics

Hero Siege
Shared: Pixel Graphics · Roguelike · RPG

Pizza Tower
Shared: Platformer · Cartoony · Pixel Graphics