Excerpt
If anything could be considered lost Zelda games... well, there's Navi Trackers, unavailable to play except in the Japanese release of the Gamecube version of Four Swords, but it's just a minigame. Then there's the disk version of Zelda II, which has substantial play differences from the cartridge versions, but it's not hard to find. There's the beta of the first Zelda, but that was never intended for public release. I hesitate to call the CDi games "real" Zelda games.
But these two games, BS Zelda and BS Zelda: Ancient Stone Tablets, are the closest there are to genuinely lost Zelda games. They were made for the Satellaview add-on for the Super Famicom, a special piece of hardware released in Japan for playing games downloaded from a satellite broadcast channel called St. Giga. This was an expensive bit of hardware: not only did you need a special package that contained devices that sat both beneath the Super Famicom and within its cartridge slot, it also had to interface with a satellite tuner, available separately and costing tens of thousands of yen, although they could be rented, and pay membership fees on top of that. Quite a lot of money for an add-on for a game system.
In exchange, however, you got access to broadcasts of game data for your Super Famicom that could be saved to the included 8MB "memory pak." There were a fair number of these games, and most of them would never be made officially available in any other format. When the service went down in 2000, the sole remaining traces of all those games left to the public were the data saved to the cartridges. Hackers, game preservationists and others continue to this day to try to rescue the data off of these carts, in some cases hacking them to produce playable game images.