2001 was supposed to see the release of UK-based Slitherine Software's Tyrannosaurus Tex, a first person shooter for the Game Boy Color which boasted smooth 3D action and a compelling deathmatch mode.
However, prospective publisher Eidos — now part of Square Enix — decided not to release the game. Slitherine couldn't find another publisher and the project foundered, with the lead programmer having a nervous breakdown and running away to Australia with the source code — his whereabouts remain unknown. Unsurprisingly, the game has been considered lost since then.
Until now, that is.
An early prototype of Tyrannosaurus Tex was auctioned in January, and the data contained on it has been preserved, documented, and publicly released by Nintendo Player.
The site has an in-depth feature on the history and development of the game, as well as screenshots taken directly from the prototype cartridge. It's a fascinating story, and well worth a read.