Games like UnDuster
Games like UnDuster include Celeste, Super Meat Boy, SANABI, Momodora: Reverie Under The Moonlight, and Jump King. We matched them by the tags players give UnDuster on Steam (Precision Platformer, 2D Platformer, Platformer, Side Scroller, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Platformer · Pixel Graphics

Super Meat Boy
Shared: Precision Platformer · Platformer · 2D Platformer

SANABI
Shared: 2D Platformer · Pixel Graphics · Platformer

Momodora: Reverie Under The Moonlight
Shared: 2D Platformer · Side Scroller · Pixel Graphics

Jump King
Shared: Precision Platformer · Platformer · Pixel Graphics

VVVVVV
Shared: Precision Platformer · Platformer · 2D Platformer

Pizza Tower
Shared: 2D Platformer · Platformer · Pixel Graphics

Thomas Was Alone
Shared: Platformer · 2D Platformer · Side Scroller

Ambidextro
Shared: Precision Platformer · 2D Platformer · Pixel Graphics

Shovel Knight: Treasure Trove
Shared: Platformer · Pixel Graphics · 2D

Mina the Hollower
Shared: 2D Platformer · Pixel Graphics · Platformer

Broforce
Shared: Pixel Graphics · Platformer · 2D

Downwell
Shared: Precision Platformer · Platformer · Pixel Graphics

The End Is Nigh
Shared: Precision Platformer · Platformer · 2D

Rain World
Shared: Atmospheric · Platformer · Pixel Graphics

Hollow Knight
Shared: Platformer · 2D · Atmospheric

Smilemo
Shared: Platformer · 2D Platformer · Side Scroller

Katana ZERO
Shared: Pixel Graphics · Platformer · 2D Platformer

Owlboy
Shared: Platformer · Pixel Graphics · 2D

Gravity Circuit
Shared: Platformer · 2D Platformer · Pixel Graphics

Lone Fungus
Shared: 2D Platformer · Pixel Graphics · Precision Platformer

Blasphemous 2
Shared: 2D Platformer · Pixel Graphics · Side Scroller

Skul: The Hero Slayer
Shared: Pixel Graphics · Platformer · 2D

Anomaly Agent
Shared: 2D Platformer · Side Scroller · Platformer