You can use this IC chip to turn SFC/SNES controller to Amiga CD32 controller. Mapping is same as CD32 one. "Select" button no use. It is...

You can use it to make Catridge Reader. Or use for development. It is not for real Game Boy. It can use for GB/GBC/GBA Cartridge.

You can use it to repair broken slot Clone SFC/SNES or use it to make Cartridge Reader.

You can use it to repair broken slot Famicom or use it to make Catridge Reader.

It is not replacement parts for NES. So, you can not use it to replace damaged NES Slot. You only can use it to make something like Cart Reader.