No Man's Sky is a space exploration and survival game where the player explores a vast, nearly-infinite universe. Starting out on one of over 18 quintillion planets, the player is first tasked with gathering the necessary materials to repair and launch their ship into space. From there, the game is entirely open ended, though the ultimate goal is to reach the center of the galaxy. Along the way, players can mine for rare and valuable elements, catalog animal and plant life, search for ruins and alien artifacts, and converse and trade items and resources with several alien factions which inhabit the universe. They can also engage in piracy by destroying other ships. Players use the resources they earn from these activities to craft upgrades for their suit, ship, and multitools.

Each planet that the player visits is procedurally generated, with its own environmental conditions, elements, and animal and plant life. Players must upgrade and configure their suit in order to adapt to the sometimes hostile environments. For example: cold planets will require the player to equip a heating mechanism in their suit. Upon visiting an unvisited planet or cataloguing a new species, players are free to name them whatever they desire - these names will be seen by other players if they reach the same location, though the chances of this are very low.

Multiplayer (both co-operative and PvP) was added in a later update. Up to 32 players can be in the same instance of a star system, and 2-4 players can be in a party.