
I took a gamble on some fishy-looking proto boards from Japan. The boards themselves have no markings, and the stickers look brand new, but all of the EPROMs were manufactured back when these games were being worked on, so I figured what the heck. Clockwise from the top-left we have Stargate, Joust, Soccer, and Hyper Olympic.
Anyway I dumped them and, hey, all but Soccer are different than the final versions. Which in itself is REALLY cool, but I want to call your attention to Joust.

Joust (along with Stargate and Millipede) were ported from the arcade originals way back in 1983 - the launch year of the Famicom - by HAL Laboratories, as contract work for Nintendo. They were, at the time, first-party games. They were made as part of Nintendo's pitch to Atari in America: if you're unaware, before the "Nintendo Entertainment System" was even a concept here, Nintendo was trying to get Atari to distribute the Famicom as its follow-up to the Atari 5200 (the 7800 was in development at the time, but wasn't announced).
Anyway, that deal fell through, and all three games were shelved. Fast forward all the way to 1987, and HAL eventually self-published its port of Joust, so technically this game was released. However, based on the other prototypes this seller had (the majority of them first-party games from 1983-1985), these appear to be from the time that it was a first-party Nintendo title. So, you might call this a prototype of an unreleased first-party Nintendo game, which is pretty cool.
What's even cooler is that it is early code! There are clear differences, including some English typos that were fixed in the final game. So, one might argue, it's an incomplete prototype of an unreleased, first-party Famicom game from its launch year. Which is amazing!
But here's the kicker: Joust was programmed by Satoru Iwata, who eventually became the president of Nintendo. It was, in fact, the first game he ever coded for Nintendo. Which means that in addition to all of the above, this is also the earliest documented Nintendo code by the friggin' legend that eventually oversaw the entire company.
Anyway. I tweeted a bit about this yesterday, and Polygon ended up writing a story, so you can see more there:
http://www.polygon.com/2016/8/16/...