Options -> display options -> opengl options -> preferences -> sprite billboard
this will make sprites display the same no matter what angle you are looking at them from. If you set it to x/y axis, this means that if you're directly above a RM or item you can still see it as if it was facing you. If it's just y-axis this means that if you're directly above a sprite, it's invisible.
x/y is almost always better except on stages like crystal or gyro that have large sprites that are broken up-- this makes them look odd.
also the last boss is almost unhittable unless you keep it on y-axis because it changes the perspective