Now listen to this one - it's really interesting.
Cuphead currently exists for 4 different platforms: Xbox One, Windows 10, Macintosh and Nintendo Switch (and on September 26 2019 what looks like a release for Tesla). For some reason it wasn't released for PS4 which is way more popular than Xbox (people still hate it nowadays and don't even hesitate to destroy Xbox 360es).
But on 2018, there was a Mexican guy who goes by the name Julio "MagnaDR" Cesar Rodríguez who, after getting a special permission from Nintendo and some tools, he started making Cuphead from scratch on the Wii U using Unity.
It is the same exact tool used for the game itself.
Notice this was the first release of the game: at the time it didn't have any secret bosses, character select nor the many language translations introduced since the Switch port. Also the Wii U alpha did not have options, little-detailed animations/screen transitions, archives for savegame, and let's not even talk about the Inkwell Isle One map being incomplete and not accessing any of the available levels so far (Forest Follies, the Root Pack and Goopy le Grande). After the Switch version was released, this project was abandoned, and MagnaDR moved on making a completely new game called "Dimensional Traveler" which plays
exactly like Cuphead but it's not about 30s stuff and such anymore. It's a totally different story.
Video about the first preview:
https://www.youtube.com/watch?v=7Yww3o90AEo
I hope someone continues this project one day, by applying the various localizations in languages and new stuff too. About the PS4, if I knew how to code I would simply extract the entire game archives from a Xbox One ISO and grouping them into a Playstation file. After that I edit some graphics to match with the Dualshock 4 controls, and install on USB and playing on a modded console. Only then Sony fans would be really happy of owning this fantastic game.