Games like GUN!GUN!!SURVIVE!!!
Games like GUN!GUN!!SURVIVE!!! include Skul: The Hero Slayer, Vampire Survivors, Hades, Rogue Legacy, and Have a Nice Death. We matched them by the tags players give GUN!GUN!!SURVIVE!!! on Steam (Action, Action Roguelike, Indie, 2D Platformer, and Top-Down Shooter): closest matches first, and among equally close ones the better-known games.

Skul: The Hero Slayer
Shared: Action · Indie · Action Roguelike

Vampire Survivors
Shared: Action Roguelike · Indie · 2D

Hades
Shared: Action Roguelike · Indie · Action

Rogue Legacy
Shared: Indie · Action Roguelike · Action

Have a Nice Death
Shared: Action Roguelike · Action · 2D

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Indie · 2D

BlazBlue Entropy Effect
Shared: Action Roguelike · Action · 2D

SANABI
Shared: Action · 2D Platformer · Indie

The Binding of Isaac
Shared: Action Roguelike · Indie · Action

Nuclear Throne
Shared: Action Roguelike · Indie · Action

20XX
Shared: Action Roguelike · Action · 2D Platformer

Pizza Tower
Shared: 2D Platformer · Indie · Action

Katana ZERO
Shared: Action · 2D Platformer · Indie

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

SYNTHETIK: Legion Rising
Shared: Action · Indie · Top-Down Shooter

UnderMine
Shared: Action Roguelike · Action · Indie

Dungreed
Shared: Action Roguelike · Action · Indie

Downwell
Shared: Action Roguelike · Indie · Action

Dust: An Elysian Tail
Shared: Action · Indie · 2D

Megabonk
Shared: Action Roguelike · Indie · Action

BALL x PIT
Shared: Action · Action Roguelike · Top-Down Shooter

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Top-Down Shooter · Action

Windowkill
Shared: Action · Action Roguelike · Indie

Risk of Rain Returns
Shared: Action Roguelike · 2D · Action