Mission codes:
X,C,T,S,X,X,X,S
T,T,C,X,T,T,X,S
C,C,C,T,X,T,S,S

10 continues, planes, and plasma shots.
Pause and select options. On the screen with Play Game
press T, S, C, S, T, S, L, L1+R1, Select, Select.
The picture to the right should now be a skull.
Now press T, S, L1, L1, L1, S, T.

Stage select:
Press Start on title screen, move cursor to Password and hold
Select while pressing T, L1, S.
Release Select and press T, L1, S, T, L1, S. A stage selection
should appear. Use left and right to select your level