Gado The Lion
-and-
Shenlong The Tiger
If you want to unlock the other things hidden in the game look into the Gamewinners.com or Gamefaqs.com data bases because iam not going to waste time posting them.
To unlockable this old school character simply complete Arcade Mode with any character.
Shenlong The Tiger
This Task is a bit harder that just completeing Arcade Mode. You have to Complete Arcade Mode but without continuing. After you beat Gado you will have only one chance to beat Shenlong in the secret stage. if you are beaten, you will have to go back in try again.
Hint-
If you are about to die use another controller in port 2 and press start... this will under a new challeger just beat Player 2 and it then will start you back to the last fight you was in. you CAN'T do this in the fight with Shenlong.