Resident Evil 0 Cheats

You can get certain prizes depending on your gameplay rank, which is how fast you beat the game on normal or hard mode.

Here are the ranks and prizes.

D:(9:01 or more) Leech Hunter and Closet Key
C:(7:01 - 9:00) Leech Hunter and Closet Key
B:(5:01 - 7:00) Leech Hunter and Closet Key
A:(3:31 - 5:00) Submachine Gun, Leech Hunter, Closet Key
S:(3:30 or less) Rocket Launcher, Submachine Gun, Leech Hunter, Closet Key

When playing as either Rebecca or Billy and you get bit by a zombie, move the character opposite of your main character directly behind the one you are controlling to have him or her shoot the zombie in the head and kill it in one hit, while the zombie deals you no damage. Note: You must have pistol equipped to save ammunition for a one bullet kill.

100 leeches: All weapons found have unlimited ammo.
90-99: Magnum revolver in room 202 of the train.
60-89: Unlimited ammo with the hunting gun.
30-59: Equipped handguns have unlimited ammo.
1-29: Sub-machinegun Bullets added to Rebecca's inventory.