Games like Odium to the Core
Games like Odium to the Core include Geometry Dash, Hollow Knight, A Dance of Fire and Ice, Hollow Knight: Silksong, and Skul: The Hero Slayer. We matched them by the tags players give Odium to the Core on Steam (Indie, Action, 2D, Stylized, and Singleplayer): closest matches first, and among equally close ones the better-known games.

Geometry Dash
Shared: Difficult · 2D · Singleplayer

Hollow Knight
Shared: Indie · 2D · Difficult

A Dance of Fire and Ice
Shared: Indie · Difficult · Singleplayer

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

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

Cuphead
Shared: Difficult · 2D · Indie

Rogue Legacy 2
Shared: Action · Indie · Arcade

Super Hexagon
Shared: Indie · Difficult · Action

Vampire Survivors
Shared: Indie · 2D · Bullet Hell

Spelunky
Shared: Indie · 2D · Difficult

Exit the Gungeon
Shared: Indie · Action · Arcade

The Binding of Isaac: Rebirth
Shared: Indie · Difficult · Singleplayer

Super Meat Boy
Shared: Indie · Difficult · 2D

Celeste
Shared: Indie · Difficult · 2D

Rogue Legacy
Shared: Indie · Action · 2D

Just Shapes & Beats
Shared: Indie · 2D · Difficult

LUFTRAUSERS
Shared: Indie · Action · 2D

Nine Sols
Shared: 2D · Action · Difficult

Shovel Knight: Treasure Trove
Shared: Indie · 2D · Action

Super Meat Boy Forever
Shared: Indie · Action · Difficult

BEEP
Shared: Indie · 2D · Singleplayer

Broforce
Shared: Action · 2D · Indie

SANABI
Shared: Action · Indie · 2D

Mark of the Ninja
Shared: Indie · 2D · Action