Like most games in The Legend of Zelda series, Link's Awakening is an action-adventure game focused on exploration and combat.[8] The majority of the game takes place from an overhead perspective.[9] The player traverses the overworld of Koholint Island while fighting monsters and exploring underground dungeons. Dungeons steadily become larger and more difficult, and feature "Nightmare" boss characters that the player must defeat, taking different forms in each dungeon, and getting harder to defeat each time.[7] Success earns the player heart containers, which increase the amount of damage the player character can survive; when all of the player's heart containers have been emptied, the game restarts at the last doorway entered by the character. Defeating a Nightmare also earns the player one of the eight instruments necessary to complete the game.