Shin Megami Tensei III: Nocturne is initially set moments before a post-apocalyptic conception of modern-day Tokyo: aside from the opening segment, post-apocalyptic Tokyo, also known as the Vortex World, is the main setting.[2] From the outset, the player can select two difficulty settings: Normal and Hard.[3] The player controls a silent protagonist who is given a name during the opening.[4][5] The player navigates the Vortex World through both a 2D world map, and to-scale 3D environments used in dungeons. While navigating the world map, the Protagonist's party and other non-player characters (NPCs), interactive objects and landmarks are represented by symbols: these objects and NPCs include containers holding items, spirits that will heal the party, and a globe in the bottom left-hand corner of the screen showing the party's approximate location on the world map. During dungeon navigation, the Protagonist navigates grid-based, multi-leveled areas. Different areas are accessed via doors, and as the Protagonist progresses the area is automatically mapped. While exploring dungeons, the in-game camera can be freely rotated, and a "Look" action allows the player to see environments in first-person.[3][6] The game world can be navigated either on foot or by using a fast travel system unlocked at a certain point in the game.[7]
Multiple important locations are located within the world: these include Terminals that give access to a fast travel system; the Junk Shop, which acts as a vendor for buying and selling items; Rag's Jewelry, where gems collected during gameplay can be traded for rare items and unique demons; and the Fountain of Life, where the Protagonist and other party members can receive treatment for ailments, heal them of damage, or revive characters knocked out in battle.[7] An optional location separate from the Vortex World is the Amala Labyrinth, accessed after the Protagonist has reached a certain point in the story. The Labyrinth is a dungeon divided into multiple floors or Kalpa, each housing both demon enemies and brokers who sell demons to the Protagonist. Each Kalpa is connected by a Warp Zone, in which the Protagonist can collect currency and items while avoiding or destroying obstacles. Proceeding through the levels of the Labyrinth requires the protagonist to find and fight Fiends carrying Candelabra, which unlock barriers. The Candelabra also act as a means of locating and either engaging or avoiding Fiends.[8]