Corridor 92
Corridor 92 was the first 3D calculator game to be released using Tom Nussbaumer's FAT engine. It is largely credited with inspiring Tom and a host of other skilled 68K programmers to add to and fine tune the engine in paralell to C92. While an amazing game for its time, it was plagued by the executible limits of 68K calculators (64K limit) and an obscene RAM requirement that couldn't be fixed without a total rewrite of the code. Its final version was released on May 12th, 2002.
It's original website (complete with downloads) is preserved [Here].