CASPER

Tons Of Stuff  In the top left corner of the main entrance, press Diag Up/<+L1+R1+Start.  Go to the first floor, and turn around so you can see the stairs you just came from.  Press R1 to float until you see a new room.  This room has all sorts of great treasures.

Turbo  During gameplay, press Triangle+X, R1, R1, R1, Triangle.