Cheats:

Enter these in the passwords section, in the options menu

Invincibility
MDLDSSLR

Unlimted Shuriken
LMDRRMSR 

Shuriken Loser
LLMSRDMS

healing Items Turned Into Sushi
SLLMRSLD

No Healing Items
DMLDMRLD

Max Ougi
RRDMLSDL