Games like RATTUS
Games like RATTUS include Bit Blaster XL, Waves, Vampire Survivors, LUFTRAUSERS, and Nova Drift. We matched them by the tags players give RATTUS on Steam (Shoot 'Em Up, Bullet Hell, Bullet Time, Time Manipulation, and Arcade): closest matches first, and among equally close ones the better-known games.

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

Waves
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Vampire Survivors
Shared: Bullet Hell · Pixel Graphics · Arcade

LUFTRAUSERS
Shared: Bullet Hell · Arcade · Shoot 'Em Up

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

Planes, Bullets and Vodka
Shared: Shoot 'Em Up · Bullet Hell · Arcade

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

ZeroRanger
Shared: Shoot 'Em Up · Bullet Hell · Arcade

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

Huntdown
Shared: Shoot 'Em Up · Side Scroller · Pixel Graphics

METAL SLUG
Shared: Arcade · Shoot 'Em Up · Side Scroller

Alex Jones: NWO Wars
Shared: Shoot 'Em Up · Arcade · Side Scroller

Super Time Force Ultra
Shared: Bullet Hell · Time Manipulation · Shoot 'Em Up

Cuphead
Shared: Bullet Hell · Cartoon · Shoot 'Em Up

DRAINUS
Shared: Shoot 'Em Up · Bullet Hell · Arcade

DEVIL BLADE REBOOT
Shared: Shoot 'Em Up · Score Attack · Bullet Hell

METAL SLUG X
Shared: Arcade · Shoot 'Em Up · Side Scroller

METAL SLUG 3
Shared: Arcade · Side Scroller · Shoot 'Em Up

DoDonPachi Resurrection
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Ikaruga
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Steredenn: Binary Stars
Shared: Shoot 'Em Up · Arcade · Bullet Hell

BLUE REVOLVER
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Blazing Chrome
Shared: Shoot 'Em Up · Side Scroller · Arcade

Savant - Ascent
Shared: Shoot 'Em Up · Bullet Hell · Score Attack