Games like Rogue Citadel
Games like Rogue Citadel include Death Must Die, Vampire Survivors, Hades, Monsters are Coming!, and Halls of Torment. We matched them by the tags players give Rogue Citadel on Steam (Tower Defense, Action Roguelike, Bullet Hell, RPG, and Base Building): closest matches first, and among equally close ones the better-known games.

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

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Hades
Shared: Action Roguelike · Roguelite · Hack and Slash

Monsters are Coming!
Shared: Tower Defense · Bullet Hell · Action Roguelike

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

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Magicraft
Shared: Action Roguelike · Bullet Hell · Roguelite

Megabonk
Shared: Action Roguelike · Bullet Hell · Roguelite

Cult of the Lamb
Shared: Action Roguelike · Base Building · Roguelite

Hades II
Shared: Action Roguelike · Roguelite · Hack and Slash

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

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

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

Necrosmith
Shared: Action Roguelike · Tower Defense · Bullet Hell

Brotato
Shared: Bullet Hell · Action Roguelike · Roguelite

Hero Siege
Shared: Action Roguelike · RPG · Hack and Slash

The Riftbreaker
Shared: Tower Defense · Base Building · Hack and Slash

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

God Of Weapons
Shared: Action Roguelike · RPG · Bullet Hell

Asgard's Fall — Viking Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

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

Moonlighter
Shared: Action Roguelike · Hack and Slash · Roguelite

UnderMine
Shared: Action Roguelike · Roguelite · RPG

Rogue Tower
Shared: Tower Defense · Strategy · Base Building