Games like Booom-Slang!
Games like Booom-Slang! include Hades, Enter the Gungeon, Blazing Beaks, Skul: The Hero Slayer, and Hades II. We matched them by the tags players give Booom-Slang! on Steam (Action, Action-Adventure, Shooter, Top-Down Shooter, and Arena Shooter): closest matches first, and among equally close ones the better-known games.

Hades
Shared: Action · Action Roguelike · Roguelike

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

Blazing Beaks
Shared: Action · Action Roguelike · Top-Down Shooter

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

Hades II
Shared: Action · Roguelike · Action Roguelike

Nuclear Throne
Shared: Action Roguelike · Action · Roguelike

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

SYNTHETIK: Legion Rising
Shared: Action · Top-Down Shooter · Action Roguelike

Brotato
Shared: Roguelike · Action Roguelike · Bullet Hell

BALL x PIT
Shared: Action · Action Roguelike · Roguelike

Megabonk
Shared: Action Roguelike · Roguelike · Action

Dead Cells
Shared: Roguelike · Action Roguelike · Action

Wizard with a Gun
Shared: Action · Action-Adventure · Roguelike

Risk of Rain 2
Shared: Action Roguelike · Action · Roguelike

BlazBlue Entropy Effect
Shared: Action · Action-Adventure · Action Roguelike

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Action

Escape From Duckov
Shared: Action · Top-Down Shooter · Shooter

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

Relic Hunters Zero: Remix
Shared: Action · Top-Down Shooter · Action Roguelike

Cinderia
Shared: Action · Action Roguelike · Roguelike

Gunfire Reborn
Shared: Roguelike · Action · Action Roguelike

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

Pathogenic
Shared: Top-Down Shooter · Roguelike · Bullet Hell

Army of Ruin
Shared: Action Roguelike · Top-Down Shooter · Shooter