Games like Two by One
Games like Two by One include Cuphead, Enter the Gungeon, BALL x PIT, Bit Blaster XL, and Sky Force Reloaded. We matched them by the tags players give Two by One on Steam (Bullet Hell, Shoot 'Em Up, Top-Down Shooter, Twin Stick Shooter, and Difficult): closest matches first, and among equally close ones the better-known games.
Cuphead
Shared: Difficult · Bullet Hell · 2D
Enter the Gungeon
Shared: Bullet Hell · Difficult · Twin Stick Shooter
BALL x PIT
Shared: Bullet Hell · Arcade · Shoot 'Em Up
Bit Blaster XL
Shared: Bullet Hell · Shoot 'Em Up · Difficult
Sky Force Reloaded
Shared: Shoot 'Em Up · Bullet Hell · Top-Down Shooter
Chippy
Shared: Bullet Hell · Shoot 'Em Up · Twin Stick Shooter
Just Shapes & Beats
Shared: Bullet Hell · Difficult · 2D
Nex Machina
Shared: Bullet Hell · Twin Stick Shooter · Shoot 'Em Up
Geometry Wars™ 3: Dimensions Evolved
Shared: Shoot 'Em Up · Twin Stick Shooter · Bullet Hell
Voidigo
Shared: Twin Stick Shooter · Bullet Hell · Shoot 'Em Up
Windowkill
Shared: Bullet Hell · Action · Arcade
Beat Hazard
Shared: Bullet Hell · Twin Stick Shooter · Shoot 'Em Up
Ikaruga
Shared: Bullet Hell · Shoot 'Em Up · Arcade
Vampire Survivors
Shared: Bullet Hell · 2D · Arcade
LUFTRAUSERS
Shared: Bullet Hell · Arcade · Shoot 'Em Up
Nuclear Throne
Shared: Bullet Hell · Difficult · Top-Down Shooter
Revolution Ace
Shared: Shoot 'Em Up · Bullet Hell · Action
Relic Hunters Zero: Remix
Shared: Twin Stick Shooter · Top-Down Shooter · Action
ZeroRanger
Shared: Shoot 'Em Up · Bullet Hell · Arcade
HELLDIVERS™ Dive Harder Edition
Shared: Top-Down Shooter · Twin Stick Shooter · Action
20 Minutes Till Dawn
Shared: Bullet Hell · Shoot 'Em Up · Top-Down Shooter
Assault Android Cactus+
Shared: Bullet Hell · Shoot 'Em Up · Twin Stick Shooter
Touhou Tenkuushou ~ Hidden Star in Four Seasons.
Shared: Bullet Hell · Shoot 'Em Up · Difficult
Cyberhunt
Shared: Shoot 'Em Up · Twin Stick Shooter · Action