In the past decade, there was a competition to promote the development of demos and games to be used on the Bung backup devices for the GameBoy. Their even wanted to build game cartridges that could be compatible with the GameBoy. And yes, some of the games were good and cool!
There was a advertisement to not use the "NINTENDO" string on the header of the binary file. This was one of the complains from Nintendo that illegal copies of games were using their registered trademark. This does not have a effect on personal computer simulations, but some people reported that headers without the "NINTENDO" word could not work property on the original hardware.
Since some people have some doubts about the reason to not build cartridges that are Nintendo compatible ...
Bung Enterprises
Other stuff ...
Sure, I do not know how this games could work into a Super GameBoy plugged into a SNES. I even wanted to get a GameBoy Color or Advance to play some games . Problems to buy a original SNES and GameBoy prevented the acquisition of the cool stuff! Even if there was a legal distributor of Nintendo parts on Brasil.