Games like Old Boy
Games like Old Boy include Celeste, Super Meat Boy, SANABI, Geometry Dash, and Downwell. We matched them by the tags players give Old Boy on Steam (Precision Platformer, 2D Platformer, Difficult, Platformer, and Parkour): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Difficult · 2D Platformer

Super Meat Boy
Shared: Precision Platformer · Difficult · Platformer

SANABI
Shared: 2D Platformer · Action · 2D

Geometry Dash
Shared: Difficult · Precision Platformer · 2D

Downwell
Shared: Precision Platformer · Platformer · 2D Platformer

VVVVVV
Shared: Precision Platformer · Platformer · 2D Platformer

Hollow Knight
Shared: Platformer · Difficult · 2D

Jump King
Shared: Precision Platformer · Difficult · Platformer

Rain World
Shared: Difficult · Platformer · 2D

I wanna be the Creator
Shared: Platformer · Precision Platformer · Action-Adventure

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

The End Is Nigh
Shared: Precision Platformer · Platformer · Difficult

Katana ZERO
Shared: Platformer · 2D Platformer · Action

Pizza Tower
Shared: 2D Platformer · Platformer · Indie

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

Mina the Hollower
Shared: 2D Platformer · Action-Adventure · Platformer

Rusted Moss
Shared: Platformer · 2D Platformer · Precision Platformer

Ambidextro
Shared: Precision Platformer · 2D Platformer · Platformer

Nine Sols
Shared: Difficult · Platformer · 2D

The Messenger
Shared: Platformer · 2D · 2D Platformer

Ori and the Will of the Wisps
Shared: Platformer · Action · Action-Adventure

Dungeon Escape
Shared: Precision Platformer · 2D Platformer · Difficult

Sonic Superstars
Shared: 2D Platformer · Platformer · Action-Adventure

MIO: Memories in Orbit
Shared: Platformer · Difficult · Action-Adventure