When The Legend of Zelda was released its gameplay defied categorization, incorporating elements from action games, adventure games, role-playing games, and puzzle games. The game begins with the player controlling Link from an overhead perspective, armed with a small shield. A sword is immediately available in a cave in front of him on the opening screen of the game. To advance, Link must explore the overworld, a large outdoor map with varied environments. Scattered across the overworld (which according to Nintendo Power, was modelled after the state of Washington) and hidden in caves, shrubbery, or behind walls are merchants, gamblers, old ladies, and other people who guide Link with cryptic clues. Barring Link's progress are creatures he must battle to locate the entrances to nine underground dungeons.
Each dungeon is a unique, maze-like collection of rooms connected by doors and secret passages and guarded by monsters different from those found on the overworld. Link must successfully navigate each dungeon to obtain one of the eight pieces of the Triforce of Wisdom. Dungeons also hide useful items, such as a boomerang for retrieving items and stunning enemies, and a recorder with magical properties. The first six dungeons have visible entrances, but the remaining three are hidden. Except for the final dungeon, which cannot be entered until the previous eight have been completed, the order of completing dungeons is somewhat arbitrary, but many dungeons can only be reached using items gained in the previous one.
Nonlinearity, the ability to take different paths to complete the game, separated Zelda from its contemporaries. Link can freely wander the overworld, finding and buying items at any point. This flexibility enables unusual ways of playing the game; for example, it is possible to reach the final boss of the game (but not defeat him) without taking a sword. Nintendo of America's management initially feared that players might become frustrated with the new concept, left wondering what to do next. As a result, the American version of the game's manual contains many hints, tips, and suggestions for players.
After completing the game, the player has access to a more difficult quest, officially referred to as the Second Quest, where dungeons and the placement of items are different and enemies stronger. Although a more difficult "replay" was not unique to Zelda, few games offered a "second quest" with entirely different levels to complete. Entering "ZELDA" as the player's name starts the second quest immediately. The Second Quest can be replayed each time it is completed.