Note: This glitch works in the Japanese PC version of the game (no NG+ there) and early versions of the English PC version (the glitch is patched in the newer versions). It does NOT work on the PSP/Vita/PS3 versions.

In lack of a better name, the glitch is used to skip numerous event flags/triggers and loading zones. Because of this, it's possible to access Grancel/Zeiss during the Prologue, thus skipping a huge portion of the game. The glitch is extremely easy to execute and only requires you to hold the 'Tab' key, regardless of it being mapped to something or not. While holding 'Tab' you will go past every event trigger and loading zone, the only exception being when an event happens right after a loading zone (like entering a building, etc.).

For more information on the glitch: