Games like Mutants (C64/Amstrad/Spectrum)
Games like Mutants (C64/Amstrad/Spectrum) include BALL x PIT, Planes, Bullets and Vodka, Hotline Miami 2: Wrong Number, Huntdown, and Hotline Miami. We matched them by the tags players give Mutants (C64/Amstrad/Spectrum) on Steam (Retro, Top-Down Shooter, Exploration, Shoot 'Em Up, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

BALL x PIT
Shared: Top-Down Shooter · Shoot 'Em Up · Arcade

Planes, Bullets and Vodka
Shared: Retro · Shoot 'Em Up · Action

Hotline Miami 2: Wrong Number
Shared: Pixel Graphics · Retro · Action

Huntdown
Shared: Pixel Graphics · Shoot 'Em Up · Retro

Hotline Miami
Shared: Pixel Graphics · Retro · Action

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

METAL SLUG
Shared: Retro · Shoot 'Em Up · Arcade

Warhammer 40,000: Boltgun
Shared: Retro · Pixel Graphics · Shooter

Bit Blaster XL
Shared: Shoot 'Em Up · Shooter · Arcade

METAL SLUG X
Shared: Retro · Shoot 'Em Up · Arcade

Cyberhunt
Shared: Shoot 'Em Up · Retro · Pixel Graphics

METAL SLUG 3
Shared: Retro · Arcade · Action

ARCADE GAME SERIES: GALAGA
Shared: Retro · Shoot 'Em Up · Arcade

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

ZeroRanger
Shared: Shoot 'Em Up · Retro · Pixel Graphics

LUFTRAUSERS
Shared: Pixel Graphics · Shoot 'Em Up · Retro

Blazing Chrome
Shared: Retro · Pixel Graphics · Shoot 'Em Up

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

Broforce
Shared: Pixel Graphics · Action · 2D

UFO 50
Shared: Retro · Pixel Graphics · Arcade

Talented
Shared: Retro · Pixel Graphics · Shoot 'Em Up

Pipistrello and the Cursed Yoyo
Shared: Exploration · Retro · Pixel Graphics

UBERMOSH Vol.5
Shared: Retro · Pixel Graphics · Top-Down Shooter

Bot Vice
Shared: Top-Down Shooter · Shoot 'Em Up · Pixel Graphics