Unlocking the four hidden characters; Falconess, Minotaur, Tigress, Jackal, is a fairly easy process. Just get to level 25 with each of the four original characters. Load your level 25 character and start a new one through character management. Hold Turbo and you will notice your character has turned into its counterpart. For example, Barbarian becomes Minotaur and Wizard becomes Jackal. They can be selected with any color.