TEKKEN 3 UNLOCKABLES
High School stage
Unlock Jin or Xiaoyu's extra costume, then get them as challenger in that costume.
Alternate introduction sequence
Complete the game with the ten base characters to view an alternate introduction featuring the characters in their two-player mode costumes. For another alternate introduction, complete the game with all characters including the secret characters.
Alternate background
Finish arcade mode with all twenty-one characters, including Gon and Dr. Boskonovitch (you also may need to complete it with Tiger). The background in practice mode changes so that Tekken 3 and King of Iron Fist Tournament 3 scrolls across behind the player selection boxes, which are now in the style of the versus board.
Tekken Ball mode
View all endings of the ten base characters to enable the "Ball Mode" option -- complete the game ten times.
Hidden characters in Tekken Ball
If you have unlocked Tekken Ball Mode without unlocking any hidden characters at all (e.g. using a GameShark code), then, including defeating Gon and unlocking him, any other characters you fight in Tekken Ball who you have not previously obtained can be accessed if you defeat them.
Theatre mode
Unlock each character, including Panda, Tiger, Doctor Boskonovitch, and Gon, and view their endings. The "Disc" and "Sound" options under "Theatre Mode" will now be available
Unlock Copper Key
Use Lei Wulong in Tekken Force Mode defeat the bosses each stages until you get the copper key.
Unlock Gon
Play Arcade mode until you unlock Tekken Ball Mode and inmediately chose only Brian, then just must win fight against him. (before better save)