Games like Marshmallow's Adventure
Games like Marshmallow's Adventure include Vampire Survivors, Rogue Legacy 2, Skul: The Hero Slayer, Megabonk, and Dead Cells. We matched them by the tags players give Marshmallow's Adventure on Steam (Arcade, Indie, Roguelike, Shoot 'Em Up, and 2D): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Indie · 2D · Roguelike

Rogue Legacy 2
Shared: Arcade · Indie · Adventure

Skul: The Hero Slayer
Shared: Indie · Roguelike · 2D

Megabonk
Shared: Roguelike · Indie · Arcade

Dead Cells
Shared: Roguelike · Adventure · 2D

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

Nova Drift
Shared: Arcade · Shoot 'Em Up · Roguelike

Rogue Legacy
Shared: Indie · Roguelike · 2D

BALL x PIT
Shared: Arcade · Roguelike · Shoot 'Em Up

Hades
Shared: Indie · Roguelike · Roguelite

Brotato
Shared: Roguelike · Singleplayer · Indie

Cyberhunt
Shared: Indie · Arcade · Shoot 'Em Up

Juicy Realm
Shared: Indie · Adventure · Roguelike

Crab Champions
Shared: Arcade · Roguelike · Indie

Spelunky
Shared: Roguelike · Indie · 2D

Halls of Torment
Shared: Roguelike · Arcade · Roguelite

Nubby's Number Factory
Shared: Roguelike · Arcade · Indie

The Binding of Isaac
Shared: Indie · Roguelike · Adventure

Cat Goes Fishing
Shared: Indie · 2D · Cute

Balatro
Shared: Roguelike · Indie · Singleplayer

Yet Another Zombie Survivors
Shared: Indie · Arcade · Roguelike

Touhou Endless Dream
Shared: Roguelike · Casual · Indie

To The Core
Shared: Arcade · 2D · Indie

Noita
Shared: Roguelike · Indie · 2D