The Battle Game is a mini-game featured exclusively on the Sega Saturn version of Resident Evil.
"You must defeat all the enemies and enter into the mysterious zone."
The mini-game can 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.
This particular mini-game 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.
During Stages 1, 6, and 11, the player has access to the Item Box, where they are able to choose equipment for the following battles. Chris and Jill are given their own unique item rosters. The items are never replenished.
The mini-game cycles through a series of 15 stages, where the player has to defeat all of the enemies within certain rooms before being able to advance. Rooms with battle segments contain standard enemies, boss enemies, and two special enemy variants. At certain points, the player is allowed to access to the Item Chest.
A final ranking, from S (best) to J (worst), is given depending on the player's remaining health, the amount of time taken to complete the stages, and the amount of ammo and restorative items left upon completion. Nothing is unlocked upon completing the mini-game.