(Hopefully) use difficulty as it should. The difficulty[0] (also called rank) varies from 0 to 32 and affects various parts of the game. The difficulty now impact those parts, but how it is modified during the gameplay is not clear. Such changes to the difficulty are not handled yet. [0] http://en.touhouwiki.net/wiki/Embodiment_of_Scarlet_Devil/Gameplay#Rank

cdef class Matrix:
    cdef public data

    cpdef flip(Matrix self)
    cpdef scale(Matrix self, x, y, z)
    cpdef scale2d(Matrix self, x, y)
    cpdef translate(Matrix self, x, y, z)
    cpdef rotate_x(Matrix self, angle)
    cpdef rotate_y(Matrix self, angle)
    cpdef rotate_z(Matrix self, angle)