Games like COSMOS
Games like COSMOS include Super Meat Boy, Celeste, Cuphead, VVVVVV, and Broforce. We matched them by the tags players give COSMOS on Steam (Precision Platformer, Platformer, Difficult, Shoot 'Em Up, and 2D Platformer): closest matches first, and among equally close ones the better-known games.
Super Meat Boy
Shared: Precision Platformer · Platformer · Difficult
Celeste
Shared: Precision Platformer · Difficult · Platformer
Cuphead
Shared: Difficult · Platformer · Local Co-Op
VVVVVV
Shared: Precision Platformer · Platformer · 2D Platformer
Broforce
Shared: Platformer · Action · Local Co-Op
Downwell
Shared: Precision Platformer · Platformer · 2D Platformer
Huntdown
Shared: Shooter · Shoot 'Em Up · Action
Jump King
Shared: Precision Platformer · Difficult · Platformer
Spelunky 2
Shared: Platformer · Difficult · 2D Platformer
SANABI
Shared: 2D Platformer · Action · Platformer
Geometry Dash
Shared: Difficult · Precision Platformer · Platformer
Katana ZERO
Shared: Platformer · Action · 2D Platformer
Bread & Fred
Shared: Precision Platformer · Difficult · 2D Platformer
Shovel Knight: Treasure Trove
Shared: Platformer · Retro · Difficult
Door Kickers: Action Squad
Shared: 2D Platformer · Action · Retro
Ambidextro
Shared: Precision Platformer · 2D Platformer · Platformer
Bit Blaster XL
Shared: Difficult · Shoot 'Em Up · Shooter
The Messenger
Shared: Platformer · Retro · 2D Platformer
Blazing Chrome
Shared: Action · Retro · Shoot 'Em Up
Pizza Tower
Shared: 2D Platformer · Platformer · Action
Duck Game
Shared: Platformer · Action · 2D
Hollow Knight
Shared: Platformer · Difficult · 2D
The End Is Nigh
Shared: Precision Platformer · Platformer · Difficult
Dungeon Escape
Shared: Precision Platformer · Difficult · Platformer