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[edit] Commodore 64

Prior to starting the game, enter the following POKES: POKE 48621,96 : SYS 32768

This will grant you Infinite Energy.

[edit] Genesis

BBKT-AA8T	Invincible!
RFKT-A6VA	Don't lose health from time passing
NPBA-FA9C + NPBA-EAG8	Select up to 99 credits per player
1BYA-E0GE	Maximum health per coin is 3,000
VBYA-FGGE	Maximum health per coin in 5,000
CBYA-ERRE	Maximum health per coin in 10,000
BJGA-AAD0 + BJGA-AADE	Start Arcade mode on Level 10
CTGA-AAD0 + CTGA-AADE	Start Arcade mode on Level 20
GJGA-AAD0 + GJGA-AADE	Start Arcade mode on Level 50
NTGA-AAD0 + NTGA-AADE	Start Arcade mode on Level 100
AKXT-AA66 + RFXT-A6X4	Infinite keys on pick-up--can switch on/off
RFXT-A6X4	You can open doors without a key
AKGT-AA5W	Infinite potions on pick-up--can switch on/off
AKGT-AA3G + AKGT-AASW	You can use a potion even if you don't have one
PB4T-ACAY	Temporary invisibility lasts ⅓ normal
DV4T-AEAY	Temporary invisibility lasts ½ normal
RB4T-ATAY	Temporary invisibility lasts 2× normal
ZB4T-A2AY	Temporary invisibility lasts 3× normal
REFA-E6YL	Temporary invisibility lasts forever