Supaplex

The game was originally designed to run on XT/AT machines (before the days of the 286 even). The speed was supposed to be 35 frames per second, which was achieved because the game waited for the vertical refresh (monitor update) which is 70 frames per second in VGA, but the game calculations were slow enough to make the game wait for two retraces.

Since the game was mostly popular on 286 and higher machines, almost everyone played (and plays!) the game at twice the intended speed.

Herman Perk disassembled the code and updated it to make the speed variable, resulting in the first SpeedFix. This was later extended to enable hidden features in the game and fix some bugs.