"You must defeat all the enemies and enter into the mysterious zone."
RE's version of Battle Game could be unlocked either by completing the game and saving the clear file, or by inputting a cheat code using a second-player controller with an RE save file set anywhere (hold X, Y, and Z and press Start at the title screen). In it, players control either Chris Redfield or Jill Valentine—the character used is determined by which save file the player selects—as they use a limited amount of ammunition and health items to kill roomfuls of zombies and other B.O.W.s, systematically being sent back to a save room to replenish their stock before advancing to the next wave. Both characters play similarly, although the exact enemies they encounter from room to room are different. As soon as the player ran out of ammunition during an attack wave, Chris/Jill would perish unless the Knife was being carried. If the player died from taking too much damage or running out of ammo, they were afforded the chance to continue, with the caveat that his time would start from where it had stopped when he died.
A ranking, from A (best) to J (worst), is given depending on time taken, how much health left, and how many items the player has left upon full completion. However, nothing additional is unlocked by playing this mode.
This particular minigame was somewhat notorious for including a zombie version of Albert Wesker as an enemy that took four shots of the Colt Python to defeat. It also housed a Gold Tyrant as the final boss; it was far more resilient to damage than the normal incarnation.
The following weapons and items are available in the save room's Item Box:
- Combat Knife
- Beretta M92FS
- Remington M870
- Colt Python
- Bazooka (Jill only)
- 75 Handgun Bullets
- 49 Shotgun Shells (Chris)/35 Shotgun Shells (Jill)
- 48 Magnum Rounds (Chris)/36 Magnum Rounds (Jill)
- 6 Explosive Rounds (Jill only)
- 6 Acid Rounds (Jill only)
- 6 Flame Rounds (Jill only)
- 4 First Aid Sprays (Chris)/5 First Aid Sprays (Jill)