It was a 2D platformer, made sometime in the 2010s.
The main character was a penguin, who used an orange sword and a blue cybernetic boomerang as weapons.
In the description, the game was called "retro" or "retro-styled", and it looked like a cross between Mega Man X and Final Ninja Zero by Nitrome.
The game I'm looking for was probably not made by Nitrome.
The first level/tutorial was called "Like You Just Woke Up".
Found it, it's Ripple Dot Zero
https://www.rippledotzero.com/