I'm so glad you liked it. The perfect ending involves needing all six character cards as well as the spell. You get a character card for saving a character from a certain predicament.
There's also lots of stuff to discover, such as an unlockable hell mode for finishing hard, alternate costumes for Hiroshi and several cheats (which can be found in a notepad file in the install folder) Also two fun easter eggs are constantly clicking on the bathroom door before you first encounter the Oni as well as an alternate Mika death scene (which is my favorite) in the basement of the Old Building (Save Anna but don't get Mika the compression kit)