Hold down together:
 
 ASDFGH  to walk thru buildings.
 QWERTYUP  unlimited energy
 
  * Please note: I have been told that the only keys that are
                 required for those two cheats are ASG and QRP.
                 I have no way of testing this and would appreciate
                 input on the matter.
 
 When you eat a pizza and leave the sewer the pizza will reappear.