The term "free roam" is also used, as is "sandbox" and "free-roaming". "Open world" and "free-roaming" suggest the absence of artificial barriers, in contrast to the invisible walls and loading screens that are common in linear level designs. The term "sandbox" is often used incorrectly. Open world doesn't necessarily mean sandbox. A true "sandbox" is where the player has tools to modify the world themselves and create how they play.
In a general sense, the concept of open-world gaming is older than the video game industry itself. As early as 1970, SEGA's electro-mechanical arcade game Jet Rocket introduced free-roaming flight movement over an open-ended 3D landscape, for the first time in an electronic game, with players being able to fly around and shoot at various landmarks across the game world. This makes it the first primitive example of an open-world game.
Early examples of free-roaming, non-linear worlds in video games, with gradually increasing open-endedness, include Bosconian (1981), Time Pilot (1982), Panorama Toh (1983), Portopia Serial Murder Case (1983), Mugen no Shinzou (1984), Dragon Slayer (1984), Ginga Hyoryu Vifam (1984), Hydlide (1984), Tritorn (1984), Elite (1984), Star Luster (1985), Brain Breaker (1985), Metroid (1986), Dragon Quest (1986), and especially the original Legend of Zelda (1986).
Released in Japan in 1984, Hydlide was an early example of a true open-world video game. It was the first game to feature on-foot, outdoor exploration in a fully-scaled, continuous, open world. It went on to influence the first Legend of Zelda, released in 1986, which adapted a similar open-world design on a larger scale. With nonlinear gameplay, it set the foundations for later action-adventure games like Metroid and role-playing video games like Final Fantasy, while influencing most modern games in general. Zelda also went on to influence the constant-scale open world designs that later appeared in Times of Lore (1988), the Ultima series from Ultima VI (1990) onwards, and the Grand Theft Auto series.
There were several early games that offered players the ability to explore an open world while driving a variety of ground vehicles. TX-1 (1983), The Battle-Road (1984) and Out Run (1986) were non-linear driving games that allowed the player to drive through multiple different paths that lead to different possible routes and final destinations. Turbo Esprit provided a 3D free-roaming city environment in 1986 and has been cited as a major influence on Grand Theft Auto. River City Ransom (1989) was an early sandbox brawler reminiscent of Grand Theft Auto. Another early open-world game reminiscent of GTA was Takeshi no Chōsenjō (Takeshi's Challenge), a 1986 Famicom game only released in Japan; it was an unusual game for its time, featuring free-roaming gameplay while, much like GTA, allowing players to randomly attack any people (and having to escape police if the player murders a person) or even punch random objects (including menus).  Another precursor was Speed Rumbler (1986), which featured a combination of run & gun shooter with driving mechanics, resulting in a new action game hybrid that would inspire games like Grand Theft Auto decades later.
Since 1991, the Metal Max series of post-apocalyptic role-playing games featured truly open-ended, non-linear gameplay. They lack a predetermined story path, but the player is instead given the choice of what missions to follow in whichever order while being able to visit any place in the game world at any time. The ending can be determined by the player, who can alter the ending through their actions, can complete the game at almost any time, and continue playing the game even after the ending. Some of the games give the player the freedom to complete the game almost immediately after starting it, particularly Metal Saga, which could be completed with a full ending scenario just minutes into the game, making it the shortest possible RPG. Since Romancing SaGa in 1992, the SaGa series has also been known for its truly open-ended, non-linear gameplay, offering many choices and allowing players to complete quests in any order, with the decision of whether or not to participate in any particular quest affecting the outcome of the storyline. The game also allowed players to choose from eight different characters, each with their own stories that start in different places and offer different outcomes. Romancing SaGa thus succeeded in providing a very different experience during each run through the game, something that even later sandbox RPGs such as Fable had promised but were unable to live up to.
Metal Max (1991) was an open-world RPG, where the player can pursue missions in any order, visit any place in the game world, determine the ending through their actions, complete the game at almost any time, and continue playing the game after the ending. Romancing Saga (1992) was an open-ended RPG by Square that offered many choices and allowed players to complete quests in any order, with the decision of whether or not to participate in any particular quest affecting the outcome of the storyline.
Some critics treat the release of Grand Theft Auto III in 2001 as a revolutionary event in the history of video games. The game's creator Sam Houser, however, described Grand Theft Auto III as "Zelda meets Goodfellas". Other critics also likened Grand Theft Auto III to The Legend of Zelda and Metroid, as well as Shenmue, and noted how GTA III had elements from earlier games. For example, open-ended missions based on operating a taxi cab in a sandbox environment were the basis for SEGA's Crazy Taxi (1999).
- ↑ 1.0 1.1 Sefton, Jamie (July 11, 2007). The roots of open-world games. GamesRadar. Retrieved on 2008-07-25.
- ↑ Logan Booker (2008-07-14). Pandemic Working On New 'Open World / Sandbox' IP. Kotaku. Retrieved on 2008-07-25.
- ↑ The complete history of open-world games (part 2). Computer and Video Games (May 25, 2008). Retrieved on 2008-07-25.
- ↑ 4.0 4.1 4.2 4.3 4.4 Harris, John (September 26, 2007). Game Design Essentials: 20 Open World Games. Gamasutra. Retrieved on 2008-07-25.
- ↑ Carl Therrien, Inspecting Video Game Historiography Through Critical Lens: Etymology of the First-Person Shooter Genre, Game Studies: The International Journal of Computer Game Research, Volume 15, issue 2, December 2015, ISSN 1604-7982
- ↑ Open-world video games at Allgame via the Wayback Machine
- ↑ Konami Classics Series: Arcade Hits - NDS - Review. GameZone (April 9, 2007). Retrieved on 2011-04-08.
- ↑ Konami Arcade Classics: Well, at least it's classic. IGN (January 7, 2000). Retrieved on 2011-04-08.
- ↑ Dark Age of JRPGs (7): Panorama Toh ぱのらま島 - PC-88 (1983), Hardcore Gaming 101
- ↑ Gingahyōryū Vifam at MobyGames
- ↑ Barton, Matt; Bill Loguidice (April 7, 2009). The History of Elite: Space, the Endless Frontier. Gamasutra. Retrieved on 2009-12-27.
- ↑ Whitehead, Dan (February 4, 2008). Born Free: the History of the Openworld Game. Eurogamer. Retrieved on 2008-07-25.
- ↑ The complete history of open-world games (part 1). Computer and Video Games (May 24, 2008). Retrieved on 2008-07-25.
- ↑ Star Luster. Virtual Console. Nintendo. Retrieved on 2011-05-08. (Translation)
- ↑ John Szczepaniak. Retro Japanese Computers: Gaming's Final Frontier. Hardcore Gaming 101. Retrieved on 2011-03-16. Reprinted from "Retro Japanese Computers: Gaming's Final Frontier", Retro Gamer (67), 2009 .
- ↑ 15 Most Influential Games of All Time: The Legend of Zelda. GameSpot. Retrieved on 2010-01-24.
- ↑ Peckham, Matt (2012-11-15). ALL-TIME 100 Video Games. TIME. Retrieved on 2014-08-12.
- ↑ Mc Shea, Tom (20121-21-12). The Legend of Zelda 25th Anniversary A Look Back. GameSpot. Retrieved on 2014-08-12.
- ↑ Computer Gaming World, issue 68 (February 1990), pages 34 & 38
- ↑ http://ign.com/articles/2001/09/10/rockstars-sam-houser-mouths-off
- ↑ 21.0 21.1 TX-1 at Museum of the Game
- ↑ 22.0 22.1 Battle-Road, The at Museum of the Game
- ↑ 23.0 23.1 Brian Gazza. Outrun. Hardcore Gaming 101. Retrieved on 2011-03-17.
- ↑ Retrorevival: Turbo Esprit, Retro Gamer issue 20, page 48. Imagine Publishing, 2006.
- ↑ Parish, Jeremy (2008-04-29). Retronauts Carjacks Grand Theft Auto. 1UP.com. Retrieved on 23 January 2012.
- ↑ The Speed Rumbler, CGR Undertow, YouTube
- ↑ Metal Max. Virtual Console. Nintendo. Retrieved on 2011-05-16. (Translation)
- ↑ Metal Max 2. Virtual Console. Nintendo. Retrieved on 2011-05-16. (Translation)
- ↑ 29.0 29.1 29.2 29.3 Metal Max (Translation), Crea-Tech
- ↑ Metal Saga - Impression, RPGamer, Spring 2006
- ↑ Romancing SaGa Review, IGN
- ↑ Patrick Gann. Romancing SaGa. RPGFan. Retrieved on 2011-03-02.
- ↑ http://www.rpgamer.com/games/other/gba/mm2kai/reviews/mm2kaistrev1.html
- ↑ Metal Max (Translation), Virtual Console, Nintendo
- ↑ Sullivan, Meghan (11 October 2005). Romancing SaGa Review. IGN. Retrieved on 15 May 2011.
- ↑ Game Informer Issue 138 p.73
- ↑ http://ign.com/articles/2001/09/10/rockstars-sam-houser-mouths-off
- ↑ Brendan Main, Lost in Yokosuka, The Escapist
- ↑ Shenmue: Creator Yu Suzuki Speaks Out, GamesTM
- ↑ Yu Suzuki, IGN
- ↑ The Disappearance of Yu Suzuki: Part 1, 1UP
- ↑ Top 25 Racing Games... Ever! Part 1. Retro Gamer (16 September 2009). Retrieved on 2011-03-17.