A single hit from enemy attack means death
Enter the following at the password screen: LDMSLRDD
All healing items turn into temaki sushi
Enter the following at the password screen: SLLMRSLD
Enemies' attack power doubled
Enter the following at the password screen: MSRLSMML
Enemies' defense power doubled
Enter the following at the password screen: SLRMLSSM
Healing items are no longer available
Enter the following at the password screen: DMLDMRLD
Ougi gauge is always full
Enter the following at the password screen: RRDMLSDL
Shuriken no longer available
Enter the following at the password screen: LLMSRDMS
Turtles can carry unlimited number of shuriken
Enter the following at the password screen: LMDRRMSR
Turtles no longer take damages
Enter the following at the password screen: MDLDSSLR
Unlock free battle arenas
Win mission 1 episode 1 - Free battle 1
Win mission 5 episode 2 - Free battle 5
Win mission 5 episode 1 - Free battle 2
Win mission 10 episode 1 - Free battle 3
Win mission 16 episode 1 - Free battle 4
Unlock score attack
Win mission 6 episode 1.
Unlock time attack
Win score attack for the first time.