Here's some codes to increase your enjoyment of the demo version.

Code        Effect
ITIHFO      Fight three rounds instead of one
ERHNE       Fight all characters instead of one
EATEE       Morphing disabled
OIVNNFOF    Tadpoles attack in lab
AOFREOIO    Opens all bonus doors
ERHYHRLY    Makes the Toadman weaker
OAOAEIOA    Autofly Mode in lab
EHRTRR      Autofly Mode in bonus rooms
OFOVH       2X in bonus rooms