Contra: Shattered Soldier Codes -

Level 7:
Finish level 6 with an "A" rank.

Level 7 in training mode:
Finish level 7 during the normal game.

30 lives:
Press (x2), (x2), , , , , , on controller two at the title screen. You will hear a sound if you have entered the code correctly. This only affects your first credit. Your remaining credits will all have the default number of lives.