On the title screen, type "HELLOIAMJMP" for infinite lives. Also, pressing 'F1'-'F8' you can access any of the towers.
If you can't collect enough weapons, type in "HOUSEBLUES" on the `up' towers, or "BLUESHOUSE" on the `down' towers.
05-----"ICEHOUSE"
09--"LANDANDLOVE"
13---"GREENTREES"