Find an area in any level where you can run back and forth reasonably far and has weapons power-ups on either side. Draw a big crowd of enemies between this area and just proceed to run back and forth. When you are ready to let loose, turn around and start to strafe. Run to the other side as you pick up all the diseased ones' health and time bonuses. When you reach the other side, take your new weapon and start again.
Unlock the following bonuses by performing the corresponding tasks:
BONUS - HOW TO UNLOCK Infinite Kaos mode time - Successfully complete all Kaos levels in arcade mode. Play as Bull - Successfully complete the East Side level in Revolution mode to unlock Bull in Kaos mode. Play as Freak - Successfully complete the Chinatown level in Revolution mode to unlock Freak in Kaos mode. Play as Spanky - Successfully complete the Mall level in Revolution mode. Chinatown level - Score 25,000 points in the Capitol City Mall level in Kaos mode. East Side level - Score 50,000 points in the Chinatown level in Kaos mode. Corporation Central level - Score 100,000 points in the East Side level in Kaos mode. Last Clone Standing levels - Successfully complete the three minute and five minute versions of a level.
Use any and all explosives to your advantage. Rocket launchers, grenade launchers, and even molotov cocktails are useful for blowing up buildings. When throwing an item into a building, face a window directly and it will go right in. Destroying buildings is where the big money is at.