Resident Evil 0 Codes -

Alternate costumes:
Successfully complete the game with any rank under the normal or hard difficulty settings. Start a new game. A Closet Key will appear in your inventory. Use it to unlock the closet in the room where the Hunting Gun was first found to access new costumes for Rebecca and Billy.

Completion bonuses:
Successfully complete the game with a "B", "C", or "D" rank to unlock the Leech Hunter mini-game.

Successfully complete the game with a time between 3:31 and 5:00 for an "A" rank to unlock the Submachine Gun and Leech Hunter mini-game.

Successfully complete the game with a time of 3:30 or faster for an "S" rank to unlock the Rocket Launcher, Submachine gun, and Leech Hunter mini-game.

Note: To a rank after completing the game it must be played under the normal difficulty setting. You will not get ranked under the easy difficulty setting, but can still unlock the Leech Hunter mini-game.

Hint: One hit kills:
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.

Hint: Extra inventory slot:
When playing as Billy with Rebecca as the alternate character, have Billy hold all the pistol ammunition for both characters and keep her gun fully loaded. This gives you one free inventory slot.

Hint: Dail door number puzzle:
Enter "4863" on Disc 2, where the cable car is located.

Hint: Brake system puzzle:
The main code is 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 7 + 2 = 81. This should activate the brakes for the train.

Hint: Fountain circle puzzle:
When you get to the fountain circle with the six animal statues on Disc 1, use Billy to light the statues in the following order: Deer, Wolf, Horse, Lion, Snake, Eagle.

Hint: Pause timed puzzles:
Try to change to your partner during a timed puzzle. Remain idle at the error message to give yourself more time to study the puzzle.

Hint: Piano room:
When you get to the piano room, make sure you have both characters with you. Have Billy play piano. A door will open by the bar. Have Rebecca go in and take the battery. The door will close. Have Billy play piano again and the door will open.

Hint: Better shotgun use:
Once you get the shotgun, do not use it. Instead, leave it in the room with the scale you put the two figures on. Find, but do not pick up, lots of shotgun ammunition. After you save her from the pit, give all the hand gun ammunition to Billy and collect the shotgun ammunition. If you get it all, she will have about 60 rounds, which is much better than using two hand guns.

Hint: Avoid Leech Zombie explosion:
When you fight the Leech Zombie, its legs will swell up at the end and explode, hurting and often killing you or your partner. There are three ways to avoid this. First, just leave as his legs are swelling but before he explodes. The second is to use a Molotov cocktail on him, which will light him on fire and melt into a puddle of slime and leeches. The third way is to kill him while he is still in "human" form, which is best done with the magnum and has the end effect as the Molotov cocktail.

Hint: Leech Hunter mini-game bonuses:
Successfully complete the Leech Hunter mini-game with one of the following ranks to unlock the corresponding bonus.

"A" rank: Unlimited ammunition for any weapon
"B" rank: Magnum
"C" rank: Hunting Gun
"D" rank: Handgun
"E" rank: Submachine Gun

Hint: Leech Hunter: Collecting Leeches:
While playing the Leech Hunter mini-game, kill everything in the Mansion, Train Tunnel, and Basement before picking up any of the leeches. Once you pick one up, you cannot put it down. Each player can find a maximum number of 50 leeches (100 total leaches in the game). One item slot can only hold 10 leeches only -- be careful.

Once you get 95 leeches, zombies will start to come back to life. Collect the leeches in the mail hall, dining room, and the second floor room where you use the MO disc last so you do not get killed.

Hint: Leech Hunter: Extra Submachine gun ammunition:
As soon as Leech Hunter starts, grab the first leech you see and run out. This will give you a clip to the machine gun.

Hint: Leech Hunter: Finding the shotgun:
When you are in the sewers, pick up the shotgun ammunition. Then, keep trying to pick up something and you will eventually find a shotgun.

Hint: Leech Hunter: Determining weapon:
There is a way to determine if you will get the submachine gun or the magnum. Look at the two herbs in front of the stairs in front of you at the start of the mini-game. If the colors are blue and green, you will get the magnum. If the colors are green and green, you will get the submachine gun. The submachine gun can do what the magnum can and requires a lot less ammunition. Green and green is highly recommended.

If you want the magnum on the Leech Hunter mini-game, load your game on Disc 1 (only if you have passed the game once and have unlocked the Leech Hunter mini-game), then play the mini-game. You will see a Green Herb and a Blue Herb, indicating that the Magnum is there. If you want the Submachine gun, load your saved file with mini-game on Disc 2 and play the mini-game. You will see two Green Herbs, indicating that the Submachine gun is in the game.

Glitch: Kill bat without bullets:
At the church run, past the bat then enter the save room. When you exit back out, you will find the bat dead.