Enter the following codes at the 'Character Selection' screen after inserting your coin to unlock the corresponding playable character.

Unlock Alex:
Press RK, Start, Up, Up.

Unlock Roger:
Press LK, Start, Up, Up.

Unlock Kunimitsu:
Press RP, Start and highlight Yoshimitsu. Then press Right, Start.

Unlock Kuma:
Press RP, Start and highlight Paul Phoenix. Then press Down, Start, Down.

Unlock Ganryu:
Press Start and highlight Michelle Chang. Then Press Start, Down, Up.

Unlock Bruce Irvin:
Press Start and highlight Lei Wulong. Then press Start 4 times and Right.

Unlock Wang Jinrey:
Press Start and highlight Baek or Jun. Press Start, Down, Right, Left, Up.

Unlock Prototype Jack:
Press Start and highlight Jack-2. Then press Down, Down and hold Start and press Up, Up.

Unlock Armor King:
Press Start and highlight King. Then press Left, hold Start, press Left, Right, release Start, press Right.

Unlock Kazuya:
Press Start and highlight Heihachi. Then press Down, Up and hold Up and press Start, Start. Release Up, then press Up.

Unlock Alternate Costumes:
Highlight any fighter and press Start.