Extreme Battle/Survival mode:
Successfully complete the game with Leon, then save the game. Then play Claire's second scenario, complete the game, and save.
Begin game play and press Select to display the options screen. Select the "Key Config" option, then hold R1 and press Square 10 times. The word "Auto" will turn red to confirm correct code entry.
Complete either character's first scenario without saving the game in under 2.5 hours with an A or B ranking for the special rocket launcher. Complete either character's second scenario without saving the game in under 2.5 hours with an A or B ranking for the special gatling gun. Complete either character's second scenario without saving the game in under 3 hours with a A or B ranking for the special machine gun. The special weapon will appear in the next game after the first chest is opened.
Final stage bonus room:
The final stage has a bonus room that can be entered through a long but easy process. In the first scenario, have Leon or Claire use the red lab key card to enter the room with the giant flying moth. Kill the moth. Find the keyboard attached to the wall, kill the larvae on it and type your name in on the keyboard as "GUEST." Register your fingerprint. Go to the first floor of the lab and find the thumbprint reader panel. Use your fingerprint, and the panel should then ask for a second "fingerprint verification." Complete the game, and save the second scenario to any file. In the second scenario from the game you have just played, go to the final stage. Find the room on the first floor of the lab where wriggling plant vines are blocking the vent. The red lab key card should be there. Take it and go to the moth room with the keyboard. Enter your name as "GUEST" and register your thumbprint. Finally, go to the first floor and find the thumbprint reader. It should ask for the "secondary fingerprint verification." Do it, and the bonus room to the right of the panel should be unlocked. Look for a special weapon inside.
For more codes, please see the normal Game Revolution Resident Evil 2 cheat page.
Thanks to Revolution readers Thug Life Member, Redbarrel, and Ian Ronan A. Viray-KIT!