Kamikaze Zombie
Beat the game on normal or hard with both Chris and Jill to unlock sporadically appearing Kamikaze zombies, which must be avoided as they pursue you throughout the mansion. Destroying them will blow up the game.
New costumes
Complete the game, then select the Once Again option. The key you have unlocks the door in the room on the second floor with the large mirror. There is a new costume inside for Jill or Chris. Beat the game again for yet another new costume.
Unlimited Rocket Launcher
Beat the game in 3 hours or less, and select the Once Again option to start with the Unlimited Rocket Launcher.
Samurai Edge
Beat the game in 5 hours or less, and select the Once Again option to start with the Samurai Edge weapon.
Real Survivor Mode
Beat the Once Again game in 5 hours or less, and unlock Real Survivor mode, which starts you with manual aiming, an unlimited handgun, and new costumes.
Invisible Enemies
Beat the game twice with Jill or Chris, to play with transparent enemies.
Special Features
Beat the game on Invisible Enemies mode in 5 hours or less to unlock special bonus features.
Almost unlimited Ammo For Gernade Launcher
Once you obtain the Gernade Launcher and another set of ammo (Flame/Acid) goto the nearest Item Box and follow these easy steps:
1. Deposit all items.
2. Pull out your Gernade Launcher (Make sure it goes to the upper-left section).
3. Pull out a case of Gernade Rounds (Make sure it goes to the upper-right section).
4. Leave Item Box.
5. Equip Gernade Launcher.
6. Re-open Item Box and deposit the Rounds (Doesn't matter where).
7. Go to the left (into the Item Box) and press A twice on the Rounds.
The Gernade Launcher should still be in your inventory with 20 rounds. Exit the Item Box and check your inventory and it should read 240 now. To get 240 of other ammo, just swap the 240 rounds with another type and repeat all steps.
Unlock Dangerous Zombie
Complete the game as both Cris and Jill to unlock the "One Dangerous Zombie" option. A special zombie will follow you and will follow you around the game and will end the game if you shoot it.
Getting the Assualt Shotgun
As Jill (why doesn't Chris get things this easy?) as you go to fight Yawn the snake Richard will be found poisoned. You are to run and get him serum within 5 minutes or he will die. If you do get the serum to him in time he will simply rest. As you go to fight Yawn the snake he will try and eat Jill but Richard being the idiot he is will be eaten instead of fending the snake off. DO NOT leave the room. Show the snake your not afraid of him and blast him back into his hole. You will see Richard's assualt shotgun lying on the floor. It holds one more round than the regular shot gun but does twice the damage and has a quicker reload time as well as greater spread range.
Getting the shot gun at the start of the game
As Jill head immediately towrds the room that contains the shotgun after Barry speaks of investigating the mansion. Take the gun from the shelf and immediately run into the room with the collapsing ceiling. Try to open the door leading out. It will be locked and run back to the other door. Its now locked to. A cut scene will occur where Jill is screaming for help as Barry blasts the door and saves her. You get the shot gun there instead of having to progress without it. In tight situations you can now pack a little extra fire power.
Immortal Wesker
As you descend to the underground lab as Chris, Lisa Trevor will appear and you and Wesker are to fend her off. Let her knock Wesker off the side of the platform and he is supposedly dead. But as you progress towards the end of the game Wesker is somehow still alive and Chris isn't making any comment towards how he survived the fall.
Hidden scenes
At the start of the game as Jill you and Barry are told to investigate. As you enter the dining room and Barry notices the blood head back toward Wesker. A message will mention you are supposed to investigate. Try to leave again and Barry will make the comment "Cold feet already Jill?" Talk to him again and Jill will automatically walk toward the clock and a door knob will be heard turning. Jill and Barry both turn in time to see a zombie come into the room and walk toward Jill. Barry will shoot it twice and kill it.