Tekken

All modes and characters:
Hold A + B and press L, R(2), L(2), Up(2), R at the main menu. Note: You may need to repeat this two or three times before it activates.
Information in this section was contributed by edward kenific.

Alternate costumes:
Press L, R, or Start at the character selection screen.

Switch fighters:
Press R at the versus screen in tag team mode.
Information in this section was contributed by Neotrainer12.

Fight as Heihachi:
Successfully complete the game with all nine characters. Heihachi will appear next to Hworang and Paul at the character selection screen.
Information in this section was contributed by geroge548.

Team battle modes:
Successfully complete arcade mode as Heihachi to unlock the and Versus Team Battle options.
Information in this section was contributed by geroge548.

Hint: Hwoarang: Dance:
Because the Disrespect move is Left, A + B, keep it and you will see Hwoarang doing a 70s-style boogie dance.
Information in this section was contributed by Michael Obed.

Hint: Heihachi: Unlimited combo:
Hold Down, Left, or Right and press A + B. This will enable him to give many punches and kicks. [Screenshot]
Information in this section was contributed by Ali Kidwai.

Hint: Hammer technique:
With Jin or Heihachi, do the Tsunami Kick when an opponent is doing an attack that involves jumping. It looks appears that they are kicked up, then suddenly hammered down. This sometimes works when the opponent is crouching.
Information in this section was contributed by Michael Obed.