Games like Empyrean Swarm
Games like Empyrean Swarm include Vampire Survivors, Halls of Torment, BALL x PIT, Enter the Gungeon, and Death Must Die. We matched them by the tags players give Empyrean Swarm on Steam (Bullet Hell, Action Roguelike, Pixel Graphics, Flight, and Top-Down Shooter): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Bullet Hell · Action Roguelike · Pixel Graphics

Halls of Torment
Shared: Action Roguelike · Bullet Hell · Pixel Graphics

BALL x PIT
Shared: Bullet Hell · Action Roguelike · Arcade

Enter the Gungeon
Shared: Bullet Hell · Action Roguelike · Pixel Graphics

Death Must Die
Shared: Bullet Hell · Action Roguelike · Pixel Graphics

Nuclear Throne
Shared: Action Roguelike · Pixel Graphics · Bullet Hell

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

Hero Siege
Shared: Pixel Graphics · Action Roguelike · RPG

Boneraiser Minions
Shared: Bullet Hell · Action Roguelike · Pixel Graphics

Brotato
Shared: Bullet Hell · Action Roguelike · Roguelike

Megabonk
Shared: Action Roguelike · Bullet Hell · Pixel Graphics

20 Minutes Till Dawn
Shared: Bullet Hell · Action Roguelike · Top-Down Shooter

Risk of Rain Returns
Shared: Action Roguelike · PvE · 2D

Tiny Rogues
Shared: Bullet Hell · Action Roguelike · Top-Down Shooter

Rogue: Genesia
Shared: Bullet Hell · Action Roguelike · Arcade

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Pixel Graphics · Indie

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · RPG

Cultivation Story: Reincarnation
Shared: Action Roguelike · Bullet Hell · RPG

Skul: The Hero Slayer
Shared: Action Roguelike · Pixel Graphics · 2D

Rogue Legacy
Shared: Action Roguelike · Pixel Graphics · RPG

Yet Another Zombie Survivors
Shared: Action Roguelike · Top-Down Shooter · Arcade

Rocket Rats
Shared: Action Roguelike · Bullet Hell · Pixel Graphics

Dungreed
Shared: Action Roguelike · Pixel Graphics · 2D

Slime 3K: Rise Against Despot
Shared: Bullet Hell · Action Roguelike · Top-Down Shooter