As a survival horror title, Resident Evil 2 features the same basic gameplay mechanics as its predecessor, Resident Evil. The player explores a fictional city while solving puzzles and fighting monsters. The game's two protagonists may be equipped with firearms, but limited ammunition adds a tactical element to weapon use. On the status screen, the player can check the condition of the protagonists, use medicine to heal their wounds, and assign weapons. The characters' current health can also be determined by their posture and movement speed. For example, a character will hold their stomach in pain if wounded, and will limp slowly if on the verge of death. The protagonists may carry a limited number of items, and must store others in boxes placed throughout the 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 main addition over the preceding game is the "Zapping System":Resident Evil 2 confronts each of the two playable characters 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 (meaning while this was going on, this was happening to the other character), is unlocked. The player has the option of starting 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 game contains three stand-alone minigames: "The 4th Survivor", "The Tofu Survivor" and "Extreme Battle". These feature an extended cast of characters, and provide goals such as surviving with no items to pick up.