Resident Evil 2 Codes -

Unlimited ammunition:
Press Up(2), Down(2), Left, Right, Left, Right, R at the item selection screen. Note: Press Up(2), Down(2), Left, Right, R at the item selection screen in the Japanese version of the game.

Extreme battle mode:
Complete both of either character's scenarios, then go to the "Special" option. A new "Extreme battle mode" selection will be unlocked.