Bonus Menu:
Go to the OPTIONS menu and hold Up + Block + Run until the screen shakes.

Background Select:
At the character select screen, highlight Sonya and press Up+Start. After you select your
character, you can then toggle through the backgrounds to choose the one you want. 

Play as Chameleon:
To play as Chameleon choose any male Ninja at the character select screen. Press and hold
Left, High Punch, Low Punch, Run and Block until the match starts. 

MK Classic Fighters:
In the player select, highlight any one of these characters; Kung Lao, Kano, Raiden or Jax and
press Select for play with classic fighters.