game world, where they may later be retrieved. Each protagonist is joined by a support partner during the course of the story. These characters accompany the player in certain scenes, and occasionally become playable. Certain rooms contain typewriters that the player may use to save the game. However, each save expends one of a limited number of ink ribbons, which the player must collect in the game world. The graphics of Resident Evil 2 are composed of real-time generated – and thus movable – polygonal character and item models, superimposed over pre-rendered backgrounds that are viewed from fixed camera angles. The game uses tank controls, meaning that pressing up moves the character forward, down reverses, and left and right rotates, independently of the camera perspective. The main addition over the preceding game is the "Zapping System", by which each of the two playable characters are confronted with different puzzles and storylines in their respective scenarios. After finishing the "A" scenario with one protagonist, a "B" scenario, in which the events are depicted from the other character's perspective, is unlocked. The player may start the "A" scenario with either of the two protagonists, resulting in a total of four different scenarios. Actions taken during the first playthrough affect the second. For example, the availability of certain items may be altered. After each game, the player receives a ranking based on the total time taken to complete the scenario, and on the number of saves and special healing items used. Depending on the player's accomplishments, bonus weapons and costumes may be unlocked as a reward. The original version of Resident Evil 2 contains two stand-alone minigames: "The 4th Survivor" and "The To-fu Survivor". In both of these minigames, the player must reach the goal while fighting every enemy along the way with only the default item loadout. All later versions (except the Nintendo 64 version) add a third minigame, "Extreme Battle", which consists of four playable characters and three stages. Plot On September 29, 1998, two months after the events of the first Resident Evil, most citizens of the Midwestern American mountain community Raccoon City have been transformed into zombies by the T-virus, a biological weapon secretly developed by the pharmaceutical company Umbrella. Leon S. Kennedy, a police officer on his first day of duty, meets Claire Redfield, a college student looking for her brother Chris. After being separated, they each make