Insert a controller in the second controller port, and at the main menu, press Up, Up, Down, Down, L1, R1, L2, R2, L3, R3.
Correct entry you will hear a sound and both players will have 30 lives in Story Mode.
At the main menu, on controller one, press Left, Right, Left, Right, Up, Down, Up, Down, Square, Circle, Square, Circle, Select, Start. (Note: If you are going to be doing this for one player, hightlight "OPTIONS", then do the code. If you are going to be doing this for two players, highlight "1 PLAYER", then do the code.)
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.
Successfully complete the game with an "A" rank to unlock the "Gallery" option.
Simply equip your Flame Thrower, and Lock your weapon on an Up-Right angle, and while standing on the ground so that your Flame is hitting under the boss's chin. For the second part, repeat the trick, but angle your gun where your Flame is hitting the monster's nose. You'll hit everything that comes outta his nose, as well as hit his mouth when he opens it. The only thing you then have to do is worry about any worms dropped on the ground from the monster.