Games like OROBOROS
Games like OROBOROS include Vampire Survivors, Brotato, BALL x PIT, Halls of Torment, and Megabonk. We matched them by the tags players give OROBOROS on Steam (Aliens, Action, Hack and Slash, Bullet Hell, and 2D): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Bullet Hell · 2D · Action Roguelike

Brotato
Shared: Bullet Hell · Singleplayer · Action Roguelike

BALL x PIT
Shared: Action · Bullet Hell · Arcade

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

Megabonk
Shared: Bullet Hell · Action · Action Roguelike

Death Must Die
Shared: Bullet Hell · Hack and Slash · Action

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

Hades
Shared: Hack and Slash · Action · Action Roguelike

Planes, Bullets and Vodka
Shared: Action · Bullet Hell · 2D

Nova Drift
Shared: Bullet Hell · Arcade · Arena Shooter

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

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

Hero Siege
Shared: Hack and Slash · Action · Top-Down

Dead Cells
Shared: 2D · Hack and Slash · Action Roguelike

Soulstone Survivors
Shared: Bullet Hell · Hack and Slash · Action

Have a Nice Death
Shared: Hack and Slash · 2D · Action

Tower of Babel: Survivors of Chaos
Shared: Bullet Hell · Action · Hack and Slash

Boneraiser Minions
Shared: Bullet Hell · 2D · Action Roguelike

Noobs Want to Live
Shared: Bullet Hell · Action · Top-Down

Exit the Gungeon
Shared: Action · Bullet Hell · Arcade

Windowkill
Shared: Action · Bullet Hell · 2D

Cyberhunt
Shared: Action · 2D · Arcade

ICEY
Shared: Action · Hack and Slash · 2D

Castle Crashers®
Shared: 2D · Hack and Slash · Action