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".
just curious but have you checked BlueMaxima's Flashpoint Archive?
It's an open-source archive that can run on both Windows and Linux
That's really cool, thanks for sharing. Delighted to find that they have the Flash version of Portal, which I discovered long before I played the real game!
https://flashpointproject.github.io/flashpoint-database/search/#b0d2b9a9-ab00-465e-b5a3-56031b92f070
no worries and yeah the OG Portal game is def fun🤗
I remember playing it before Valve's version came out and thinking they made a quite a fun and interesting improvement to the original concept/mechanic!