Games like Hoppup!
Games like Hoppup! include Celeste, Jump King, Super Meat Boy, VVVVVV, and SANABI. We matched them by the tags players give Hoppup! on Steam (Precision Platformer, Psychological Horror, Platformer, 2D Platformer, and Indie): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Platformer · Indie

Jump King
Shared: Psychological Horror · Precision Platformer · Indie

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

VVVVVV
Shared: Precision Platformer · Platformer · Pixel Graphics

SANABI
Shared: Pixel Graphics · 2D Platformer · Adventure

Downwell
Shared: Precision Platformer · Platformer · Indie

Pogostuck: Rage With Your Friends
Shared: Psychological Horror · Precision Platformer · Platformer

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

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

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

Geometry Dash
Shared: Precision Platformer · Difficult · Platformer

A Difficult Game About Climbing
Shared: Psychological Horror · Precision Platformer · Platformer

Pizza Tower
Shared: 2D Platformer · Indie · Platformer

Rain World
Shared: Difficult · Indie · Platformer

Getting Over It with Bennett Foddy
Shared: Psychological Horror · Difficult · Platformer

Shovel Knight: Treasure Trove
Shared: Platformer · Pixel Graphics · Indie

Ambidextro
Shared: Precision Platformer · 2D Platformer · Platformer

Hollow Knight
Shared: Platformer · Indie · Difficult

Skul: The Hero Slayer
Shared: Indie · Pixel Graphics · Action

Rusted Moss
Shared: Platformer · Pixel Graphics · Precision Platformer

Windswept
Shared: Platformer · Precision Platformer · 2D Platformer

Blasphemous 2
Shared: Difficult · Adventure · 2D Platformer

Bread & Fred
Shared: Precision Platformer · 2D Platformer · Pixel Graphics

Hollow Knight: Silksong
Shared: Indie · Difficult · Platformer