For the digital age! You get the full game as a ROM to run in an emulator, the full instruction booklet as a PDF file, and the soundtrack in a digital format, so you can listen to it on the morning commute.
The cartridge in this reward is special. It is yellow, just like a perfect banana, and it comes in a special box. Add to this some stickers and the official Soko Banana t-shirt, and you have the Limited Special Edition.