Games like Deneb: Across the Stars
Games like Deneb: Across the Stars include Celeste, Jump King, Super Meat Boy, SANABI, and VVVVVV. We matched them by the tags players give Deneb: Across the Stars on Steam (Precision Platformer, Difficult, Psychological Horror, Pixel Graphics, and Singleplayer): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Difficult · Pixel Graphics

Jump King
Shared: Difficult · Precision Platformer · Psychological Horror

Super Meat Boy
Shared: Precision Platformer · Difficult · Pixel Graphics

SANABI
Shared: Pixel Graphics · Singleplayer · 2D Platformer

VVVVVV
Shared: Precision Platformer · Pixel Graphics · Difficult

Geometry Dash
Shared: Difficult · Precision Platformer · Singleplayer

Rain World
Shared: Difficult · Atmospheric · Pixel Graphics

Downwell
Shared: Precision Platformer · Pixel Graphics · Difficult

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

Hollow Knight
Shared: Difficult · Platformer · Singleplayer

Hollow Knight: Silksong
Shared: Difficult · Singleplayer · Indie

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

Hyper Light Drifter
Shared: Pixel Graphics · Difficult · Atmospheric

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

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

Hotline Miami 2: Wrong Number
Shared: Pixel Graphics · Difficult · Top-Down

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

Titan Souls
Shared: Difficult · Pixel Graphics · Singleplayer

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

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

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

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

Hotline Miami
Shared: Pixel Graphics · Top-Down · Difficult

Changed
Shared: Difficult · Psychological Horror · Singleplayer