Games like Simple Spy
Games like Simple Spy include Hollow Knight, Minimalism, Hollow Knight: Silksong, Skul: The Hero Slayer, and Nine Sols. We matched them by the tags players give Simple Spy on Steam (Action, Indie, Platformer, 2D, and Minimalist): closest matches first, and among equally close ones the better-known games.

Hollow Knight
Shared: Platformer · Indie · 2D

Minimalism
Shared: Indie · Action · Platformer

Hollow Knight: Silksong
Shared: Indie · 2D · Difficult

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

Nine Sols
Shared: Action · 2D · Platformer

BEEP
Shared: Indie · Platformer · 2D

LIMBO
Shared: Indie · Platformer · 2D

Shovel Knight: Treasure Trove
Shared: Platformer · Indie · Action

Dust: An Elysian Tail
Shared: Action · Platformer · Indie

Celeste
Shared: Indie · Platformer · Difficult

Cuphead
Shared: Platformer · Difficult · 2D

Broforce
Shared: Action · 2D · Platformer

Rogue Legacy 2
Shared: Action · Platformer · Indie

Jump King
Shared: Indie · Platformer · Difficult

Pikuniku
Shared: Indie · Casual · Adventure

SANABI
Shared: Action · Indie · 2D

No Time To Explain Remastered
Shared: Action · Indie · Platformer

BADLAND: Game of the Year Edition
Shared: Indie · Action · 2D

Geometry Dash
Shared: 2D · Difficult · Platformer

Super Fancy Pants Adventure
Shared: Action · Indie · Platformer

Angvik
Shared: Indie · Action · Platformer

Spelunky
Shared: Platformer · Indie · 2D

Defy Gravity Extended
Shared: Indie · Platformer · Action

Katana ZERO
Shared: Action · Platformer · Indie

