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
For markets in the Western hemisphere, the genre's popularity peaked during the late 1980s to mid-1990s when many considered it to be among the most technically advanced genres, but had become a niche genre in the early 2000s due to the popularity of first-person shooters and became difficult to find publishers to support such ventures. Since then, a resurgence in the genre has occurred spurred on by success of independent video game development, particularly from crowdfunding efforts, the wide availability of digital distribution enabling episodic approaches, and the proliferation of new gaming platforms including portable consoles and mobile devices; "The Walking Dead" is considered to be a key title that rejuvenated the genre.