Contra: Shattered Soldier (PS2)

Get 30 lives
Using player 2's controller press: up,up,down,down,L1,R1,L2,R2,L3,R3 at the menu screen.
Please notice that this will affect only your first credit; the other credits you use will still have just three lives. ["R3" and "L3" mean you have to press the right and left stick like a button.]

Completion Bonuses rating
Successfully complete the game on the normal difficulty setting with at least a 'B' rank to unlock the 'Theater' option, 'Database' option, and level 5 in training mode.

Successfully complete the game with an 'A' rank to view an alternate ending sequence and unlock level 6 in training mode.

Unlockable Stages
Unlock more stages in Story Mode by doing the following:
Level 6 - Clear level 5 with rank "A"
Level 7 - Clear level 6 with rank "A"

Unlock more training stages by doing the following
Level 5 - Clear level 5 on normal.
Level 6 - Clear level 6 on normal.
Last Boss - Kill last boss on normal.

Extras
Database - Clear game with rank "B"
Gallery - Clear game with rank "A"
Return - Clear game with rank "A"
Satellite - Clear game with rank "B"
Theater - Clear game with rank "B"