BHRA-EAGC Start a new game with 9 lives (medium difficulty only)
CXRA-EAGC Start a new game with 20 lives (medium difficulty only)
ADTT-AAF4 + ACFT-EAEN + ACGA-EABJ + ACGA-EAHT Infinite energy. You can still die if Elmer gets you
AWPT-EA2W Invincibility. You can still die if Elmer gets you. If
the invincibility code doesn't work later on in the 
game, try adding this code: AXVT-AA4Y