Games like XENOCIDE PROTOCOL
Games like XENOCIDE PROTOCOL include Vampire Survivors, Megabonk, Halls of Torment, BALL x PIT, and Death Must Die. We matched them by the tags players give XENOCIDE PROTOCOL on Steam (Action, Action Roguelike, Bullet Hell, Roguelite, and 2D): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Megabonk
Shared: Action Roguelike · Roguelite · Bullet Hell

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

BALL x PIT
Shared: Action · Roguelite · Bullet Hell

Death Must Die
Shared: Action Roguelike · Bullet Hell · Roguelite

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Roguelite · Bullet Hell

20 Minutes Till Dawn
Shared: Action Roguelike · Bullet Hell · Roguelite

Brotato
Shared: Bullet Hell · Action Roguelike · Roguelite

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

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

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

Tower of Babel: Survivors of Chaos
Shared: Action Roguelike · Bullet Hell · Roguelite

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Nuclear Throne
Shared: Action Roguelike · Action · Bullet Hell

Hades
Shared: Action Roguelike · Roguelite · Action

Boneraiser Minions
Shared: Action Roguelike · Bullet Hell · Roguelite

Monsters are Coming!
Shared: Action · Roguelite · Bullet Hell

I Am Legion: Stand Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Star of Providence
Shared: Action Roguelike · Bullet Hell · Roguelite

Nova Drift
Shared: Bullet Hell · Roguelite · Action Roguelike

Nordic Ashes: Survivors of Ragnarok
Shared: Action Roguelike · Bullet Hell · Roguelite

Atomicrops
Shared: Action · Bullet Hell · Action Roguelike

Magicraft
Shared: Action Roguelike · Bullet Hell · Roguelite

Arms of God
Shared: Action Roguelike · Bullet Hell · Action