All additional components purchased and ready to go. So far I have prepared the game cartridge cutting all required holes for ports and trimmed some plastic from the bottom to make the Raspberry Pi . First time cutting plastic to create port holes so it's a little rough but not bad for a first attempt.

I opted to use a larger EA game cartridge rather than the smaller Sega. Here are a few images:

Game cartridge port holes cut:

Rough internal layout: