Games like The Castle Burns!
Games like The Castle Burns! include Vampire Survivors, Have a Nice Death, Brotato, Death Must Die, and Enter the Gungeon. We matched them by the tags players give The Castle Burns! on Steam (Action Roguelike, Bullet Hell, Arena Shooter, Funny, and 2D): closest matches first, and among equally close ones the better-known games.

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

Have a Nice Death
Shared: Action Roguelike · 2D · Funny

Brotato
Shared: Bullet Hell · Action Roguelike · Roguelike

Death Must Die
Shared: Action Roguelike · Bullet Hell · 2D

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

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

Noobs Are Coming
Shared: Action Roguelike · Arena Shooter · Bullet Hell

DELTARUNE
Shared: Funny · Bullet Hell · 2D

Megabonk
Shared: Action Roguelike · Bullet Hell · Roguelike

Rabbit and Steel
Shared: Bullet Hell · Action Roguelike · 2D

Nova Drift
Shared: Bullet Hell · Action Roguelike · Arena Shooter

South Park™: The Stick of Truth™
Shared: Funny · Comedy · 2D

Voidigo
Shared: Action Roguelike · Bullet Hell · Roguelike

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

God Of Weapons
Shared: Action Roguelike · Bullet Hell · Arena Shooter

Rogue Legacy
Shared: Action Roguelike · Roguelike · 2D

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

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Roguelike · 2D

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelike

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

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

Hades
Shared: Action Roguelike · Roguelike · Indie

Nuclear Throne
Shared: Action Roguelike · Bullet Hell · Roguelike

Dead Cells
Shared: Action Roguelike · Roguelike · 2D