Play As Sonork:
At title screen hit: L, R, C-up, C down, C-left, C-right

Play as Demitron and Sonork:
At title screen hit: A, B, R, L, C-down, C-up

See Character Endings:
Aaron: At title screen hit: Up, C-left, R, Right, down,8 R, R, C-left
Demonica: Hit: " "R, R, C-up
Demitron: " "L, L, C-down
Eve: " "R, R, C-right
Gore: " "R, R, C-down
Morphix: " "R, R, B
Niiki: " "R, R, A
Scarlet: " "L, L, C-left
Sonork: " "L, L, C-up
Zenmuron: " "L, L, C-right