Play as Sonork: At the title screen, press L, R, Top C, Bottom C, Left C, and Right C.
Play as Demitron: At the title screen, press A, B, R, L, Bottom C, and Top C.
See the Endings
Enter any of the following codes at the title screen for these character endings:
Aaron: Press Up, Left C, R, Right, Down, R, R, Left C.
Demonica: Press Up, Left C, R, Right, Down, R, R, Top C.
Demitron: Press Up, Left C, R, Right, Down, L, L, Bottom C.
Eve: Press Up, Left C, R, Right, Down, R, R, Right C.
Gore: Press Up, Left C, R, Right, Down, R, R, Bottom C.
Morphix: Press Up, Left C, R, Right, Down, R, R, B.
Nikki: Press Up, Left C, R, Right, Down, R, R, A.
Scarlet: Press Up, Left C, R, Right, Down, L, L, Left C.
Sonork: Press Up, Left C, R, Right, Down, L, L, Top C.
Zenmuron: Press Up, Left C, R, Right, Down, L, L, Right C.