If you use the Konami code (U,U,D,D,L,R,L,R,B,A) at the title screen. You will hear the turtles yell cowabunga, and it will show cowabunga as well.


Passwords

In the "Options" menu select "Input Password" and enter any of the following:

Password  Effect
SRDSLLMS  Crystals become Easter Eggs
DRSSMRLD  Crystals become Jack-O-Lanterns
LLDMSRMD  Crystals become Santa
DDRMLRDS  Life Icons become Pizza