Games like Retrograde Arena
Games like Retrograde Arena include Waves, Nex Machina, Sky Force Reloaded, Chippy, and BALL x PIT. We matched them by the tags players give Retrograde Arena on Steam (Bullet Hell, Twin Stick Shooter, Shoot 'Em Up, Top-Down Shooter, and Arcade): closest matches first, and among equally close ones the better-known games.

Waves
Shared: Bullet Hell · Twin Stick Shooter · Shoot 'Em Up

Nex Machina
Shared: Bullet Hell · Twin Stick Shooter · Arcade

Sky Force Reloaded
Shared: Bullet Hell · Shoot 'Em Up · Top-Down Shooter

Chippy
Shared: Bullet Hell · Twin Stick Shooter · Shoot 'Em Up

BALL x PIT
Shared: Bullet Hell · Arcade · Shoot 'Em Up

Nova Drift
Shared: Bullet Hell · Shoot 'Em Up · Arcade

Sektori
Shared: Twin Stick Shooter · Shoot 'Em Up · Bullet Hell

Beat Hazard
Shared: Twin Stick Shooter · Bullet Hell · Shoot 'Em Up

Bit Blaster XL
Shared: Bullet Hell · Shoot 'Em Up · Arcade

The Ascent
Shared: Top-Down Shooter · Shooter · Cyberpunk

Assault Android Cactus+
Shared: Bullet Hell · Twin Stick Shooter · Shoot 'Em Up

Beat Hazard 2
Shared: Twin Stick Shooter · Bullet Hell · Top-Down Shooter

State of Anarchy: Master of Mayhem
Shared: Bullet Hell · Top-Down Shooter · Twin Stick Shooter

KILL KNIGHT
Shared: Bullet Hell · Top-Down Shooter · Arcade

Relic Hunters Zero: Remix
Shared: Twin Stick Shooter · Top-Down Shooter · Bullet Hell

Revolution Ace
Shared: Shoot 'Em Up · Bullet Hell · Shooter

Voidigo
Shared: Twin Stick Shooter · Bullet Hell · Shoot 'Em Up

Titan Attacks!
Shared: Bullet Hell · Shoot 'Em Up · Twin Stick Shooter

Geometry Wars™ 3: Dimensions Evolved
Shared: Twin Stick Shooter · Bullet Hell · Shoot 'Em Up

DoDonPachi Resurrection
Shared: Bullet Hell · Shoot 'Em Up · Top-Down Shooter

Bot Vice
Shared: Bullet Hell · Top-Down Shooter · Shoot 'Em Up

Warhammer 40,000: Shootas, Blood & Teef
Shared: PvP · Bullet Hell · Shoot 'Em Up

RUINER
Shared: Top-Down Shooter · Twin Stick Shooter · Cyberpunk