The console and all the games were purchased at a garage sale sometime in the mid 80s. My brother and I played these games as kids not realizing what they were at the time. Prototype, weird black cartridge, whatever.. they were just games to us.
We played the hell out of the Atari until the Nintendo hit the scene. After that the console, all games, and game center were shelved. I've been holding onto it, as well as some other retro electronics from my youth like my Commodore 64 and 128.
Fast forward 30+ years and while moving I'm browsing through the box its in and the games and pull out these prototypes. Wow! As an adult now and realizing what they were It was like finding treasure that I didn't know I had. I can only assume the person who sold them at the garage sale 30+ years ago must have had some connection with Atari in some way. I don't really know who all got these prototypes back in the day.
Not really sure how rare these are in general but its been fun trying to educate myself on these as a lifelong gamer.