In 2016, a fan released AM2R, a full remake of Metroid II.
He had spent around 10 years making it.
Days after release, Nintendo issued DMCA takedowns and the project was officially stopped.
I can overlook how it's just a glorified license key, but the bigger problem with how 3rd party publishers are forcing everyone to buy their GKCs, is storage space. You're literally forcing all these people to get bigger internal storage with more proprietary Micro SD cards.