Games like Jump4
Games like Jump4 include Celeste, Super Meat Boy, SANABI, VVVVVV, and Downwell. We matched them by the tags players give Jump4 on Steam (Precision Platformer, 2D Platformer, Singleplayer, Pixel Graphics, and Puzzle Platformer): closest matches first, and among equally close ones the better-known games.

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

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

SANABI
Shared: Pixel Graphics · 2D Platformer · Singleplayer

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

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

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

Geometry Dash
Shared: Precision Platformer · Singleplayer · 2D

Jump King
Shared: Precision Platformer · Pixel Graphics · Indie

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

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

Webbed
Shared: 2D Platformer · Pixel Graphics · Puzzle Platformer

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

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

Gravity Circuit
Shared: Pixel Graphics · Singleplayer · Indie

Thomas Was Alone
Shared: 2D Platformer · Precision Platformer · Platformer

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

NINJA GAIDEN: Ragebound
Shared: 2D Platformer · Pixel Graphics · Platformer

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

LIMBO
Shared: Puzzle Platformer · Indie · Platformer

Braid
Shared: 2D Platformer · Puzzle Platformer · Indie

Hollow Knight
Shared: Platformer · Singleplayer · Indie

Rain World
Shared: Pixel Graphics · Indie · Platformer

Electronic Super Joy
Shared: Indie · Platformer · Singleplayer

Out There Somewhere
Shared: Pixel Graphics · Platformer · Indie