Resident Evil: Biohazard

Rocket launcher
Finish the game in under three hours without rescuing anyone. If done correctly, a rocket will appear after the credits. Save the game. Then, start the game that was just saved and the rocket launcher with infinite ammunition will be available. Note: The rocket launcher does not shoot well upwards or downwards.

Alternate clothes
Rescue the other two players and finish the game. If done correctly, the phrase "You've got the special key" will appear after the credits. Save the game. Start the game that was just saved. Enter the room with the large mirror on the second floor of the mansion. Unlock the door in the back. Enter the closet and move all the way to the end of the rack of clothes. Then, a message asking "There is an outfit that fits you perfectly, do you want to put it on?" will appear. Now select "Yes" to change your character's clothes.

Reset game
Pause the game and press Start + Select. Then the game will reset and return to the main menu.

Configure game (Japanese version)
Pause the game and press Start + Select. Now game options may be changed before resuming the game.

Change difficulty during game (Japanese version)
Note: The game must have been previously completed on the hard difficulty setting. At the title screen, press R1, L2, R2, L1, X, Triangle, X, Square. If you entered the code correctly, you will hear the sound of a zombie. Now while playing the game, hold R1 + R2 + L1 + L2 and press Select to change the difficulty.