To play a game on Easy difficulty where there are double the amount of normal items, go to the Main Menu and hold Right until the "New Game" option turns green. Additionally, hold Right while "Rebirth Mode" is highlighted to play both Rebirth and Classic modes on Easy.
When you shoot a zombie down to the floor, wait an extra moment to make sure a pool of blood forms around them. Sometimes zombies will lay, waiting for you to pass so they can grab you. If there's no pool of blood, shoot extra rounds from your weapon.
Unlock the following characters for play in Multiplayer mode by performing the corresponding tasks:
CHARACTER - HOW TO UNLOCK Albert Wesker - Get a "B" or higher rank in the Masters Of Knifing mini-game. Barry Burton - Beat Rebirth mode with Jill. Enrico Marini - Beat all Co-Op levels in Multiplayer mode. Forest Speyer in Multiplayer mode - Beat Classic mode with Jill. Kenneth J. Sullivan in Multiplayer mode - Beat Classic mode with Chris. Rebecca Chambers in Multiplayer mode - Beat Rebirth mode with Chris. Richard Aiken in Multiplayer mode - Beat all Versus mode levels in Multiplayer mode. Rocket Launcher - Beat the game in less than three hours. Then, start a new game from your cleared save game file.
Take the four empty bottles and mix #2 with water to create #3. Mix #2 and #4 to get yellow chemical. Mix yellow chemical with water for #7. Mix #2 and #4 a second time for yellow chemical. Mix yellow chemical and #7 for #13. Mix #13 and #3 for V-JOLT.
To unlock alternate costumes, you must first beat Jill Valentine's scenario with Barry Burton alive or Chris Redfield's scenario with Rebecca Chambers alive. Then, save the game and load the cleared save game file to start with the Special Key in your inventory. Use the Special Key to unlock closet in Mansion 1F to access alternate costumes. The costumes are different in Classic and Rebirth modes.
Note: This requires an Action Replay DS. Go to the nearest save room and grab the four crests out of the item box. Now go to the Guardhouse, get the Room 002 key, and go to Room 002. When you try to open it, you will hear Barry's voice speaking with someone. Go through the door after for the rest of the scene.