Games like Gladiator's Arena
Games like Gladiator's Arena include Vampire Survivors, BALL x PIT, Nuclear Throne, Brotato, and Enter the Gungeon. We matched them by the tags players give Gladiator's Arena on Steam (Action Roguelike, Bullet Hell, Top-Down Shooter, Medieval, and Roguelike): closest matches first, and among equally close ones the better-known games.

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

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

Nuclear Throne
Shared: Action Roguelike · Roguelike · Bullet Hell

Brotato
Shared: Bullet Hell · Action Roguelike · Roguelike

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

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

Megabonk
Shared: Action Roguelike · Roguelike · Bullet Hell

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

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

Realm of the Mad God Exalt
Shared: Bullet Hell · Roguelike · Action Roguelike

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

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

Noobs Want to Live
Shared: Bullet Hell · Roguelike · Action Roguelike

Hero Siege
Shared: Action Roguelike · Pixel Graphics · Roguelike

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelike

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

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

Rogue Legacy
Shared: Action Roguelike · Roguelike · Action

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

Sephiria
Shared: Action Roguelike · Roguelike · Action

FatalZone
Shared: Action Roguelike · Bullet Hell · Top-Down Shooter

Risk of Rain (2013)
Shared: Action Roguelike · Roguelike · Action

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

The Binding of Isaac
Shared: Action Roguelike · Roguelike · Action