Games like Gunslugs 2
Games like Gunslugs 2 include Broforce, Skul: The Hero Slayer, Shovel Knight: Treasure Trove, SANABI, and Huntdown. We matched them by the tags players give Gunslugs 2 on Steam (Action, Indie, Platformer, Shoot 'Em Up, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Broforce
Shared: Action · Pixel Graphics · Platformer

Skul: The Hero Slayer
Shared: Action · Indie · Pixel Graphics

Shovel Knight: Treasure Trove
Shared: Platformer · Indie · Pixel Graphics

SANABI
Shared: Action · Pixel Graphics · Indie

Huntdown
Shared: Action · Pixel Graphics · Shooter

Hotline Miami
Shared: Action · Indie · Pixel Graphics

Katana ZERO
Shared: Action · Pixel Graphics · Platformer

Blazing Chrome
Shared: Action · Indie · Pixel Graphics

Risk of Rain (2013)
Shared: Indie · Action · Platformer

The Messenger
Shared: Platformer · Retro · Pixel Graphics

UFO 50
Shared: Indie · Action · Pixel Graphics

Cuphead
Shared: Platformer · Indie · Difficult

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

Super Meat Boy
Shared: Platformer · Indie · Pixel Graphics

Rogue Legacy
Shared: Platformer · Indie · Action

BlazBlue Entropy Effect
Shared: Action · Platformer · Pixel Graphics

LUFTRAUSERS
Shared: Indie · Action · Pixel Graphics

Out There Somewhere
Shared: Platformer · Indie · Pixel Graphics

Downwell
Shared: Indie · Pixel Graphics · Platformer

Celeste
Shared: Indie · Pixel Graphics · Platformer

Bleed
Shared: Action · Indie · Platformer

Duck Game
Shared: Action · Pixel Graphics · Platformer

Vampire Survivors
Shared: Pixel Graphics · Indie · Action

The Binding of Isaac: Rebirth
Shared: Indie · Pixel Graphics · Roguelike