Open world
There is no consensus on what the earliest open world game is, due to differing definitions of how large or open a world needs to be. Ars Technica traces the concept back to the free-roaming exploration of 1976 text adventure game "Colossal Cave Adventure", which inspired the free-roaming exploration of "Adventure" (1980), but notes that it wasn't until 1984 that what "we now know as open-world gaming" took on a "definite shape" with 1984 space simulator "Elite", considered a pioneer of the open world; Gamasutra argues that its open-ended sandbox style is rooted in flight simulators, such as SubLOGIC's "Flight Simulator" (1979/1980), noting most flight sims "offer a 'free flight' mode that allows players to simply pilot the aircraft and explore the virtual world". Others trace the concept back to 1981 CRPG "", which had a free-roaming overworld map inspired by tabletop RPG "Dungeons & Dragons". The overworld maps of the first five "Ultima" games, released up to 1988, lacked a single, unified scale, with towns and other places represented as icons; this style was adopted by the first three "Dragon Quest" games, released from 1986 to 1988 in Japan.
Adventure game
Text adventures convey the game's story through passages of text, revealed to the player in response to typed instructions. Early text adventures, "Colossal Cave Adventure", "Hugo's House of Horrors" and Scott Adams' games, used a simple verb-noun parser to interpret these instructions, allowing the player to interact with objects at a basic level, for example by typing "get key". Later text adventures, and modern interactive fiction, use natural language processing to enable more complex player commands like "take the key from the desk". Notable examples of advanced text adventures include most games developed by Infocom, including "Zork" and "The Hitchhiker's Guide to the Galaxy". With the onset of graphic adventures, the text adventure fell to the wayside, though the medium remains popular as a means of writing Interactive Fiction (IF), which tend to be focused more on the narrative through player exploration and discovery rather than puzzle solving. Interactive fiction may include puzzles, but these tend to be incorporated as part of the narrative in comparison to being specifically added as gameplay that must be solved to continue within adventure games.