The King of Fighters XI: Hidden Content in the Arcade Version
Time Release Options
There is a hidden 4th page in the system menu of the game. On this page, the hidden time-release characters can be unlocked manually. There is currently no known way to access the page on real hardware (the screenshot has been taken from an emulator).
To access this page, set the page index of the test menu to a different number (via memory editing, eg. Cheat Engine).
We asked for help from Sudden-Desu, who is an expert on hacking into games to find hidden content. His findings on KOFXI are documented here.
Text found in the unencrypted atomiswave .bin (and in the PS2 version) of the game hints at the existence of a Debug-Menu. There currently is no known way to access it.