Games like SUBSØNIC
Games like SUBSØNIC include Beat Hazard, Waves, Beat Hazard 2, Beat Hazard 3, and Greedland. We matched them by the tags players give SUBSØNIC on Steam (Bullet Hell, Twin Stick Shooter, Music-Based Procedural Generation, Rhythm, and Shoot 'Em Up): closest matches first, and among equally close ones the better-known games.

Beat Hazard
Shared: Twin Stick Shooter · Music-Based Procedural Generation · Bullet Hell

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

Beat Hazard 2
Shared: Music-Based Procedural Generation · Rhythm · Twin Stick Shooter

Beat Hazard 3
Shared: Music-Based Procedural Generation · Bullet Hell · Rhythm

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

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

Windowkill
Shared: Bullet Hell · Action · Twin Stick Shooter

Symphony
Shared: Shoot 'Em Up · Bullet Hell · Rhythm

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

Enter the Gungeon
Shared: Bullet Hell · Twin Stick Shooter · Action

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

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

Geometry Wars™ 3: Dimensions Evolved
Shared: Twin Stick Shooter · Bullet Hell · Action

Just Shapes & Beats
Shared: Bullet Hell · Rhythm · Action

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

AudioSurf
Shared: Rhythm · Music-Based Procedural Generation · Score Attack

Melody's Escape
Shared: Music-Based Procedural Generation · Rhythm · Action

Sky Force Reloaded
Shared: Bullet Hell · Shoot 'Em Up · Action

KILL KNIGHT
Shared: Bullet Hell · Twin Stick Shooter · Score Attack

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

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

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

Beat Saber
Shared: Rhythm · Music-Based Procedural Generation · Action

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