To unlock characters in Kaos Mode, finish these challenges:

Spanky: Complete the Mall in Revolution Mode
Freak: Complete Chinatown in Revolution Mode
Bull: Complete East Side in Revolution Mode

To get unlimited time, beat Arcade Mode in all Kaos maps.

To unlock the following maps in Kaos mode, complete the challenges listed:

Chinatown: Get 25,000 points in Kaos Mode in Capitol City Mall
East Side: Get 50,000 points in Kaos Mode in Chinatown
Corporation Central: Get 100,000 points in Kaos Mode in East Side