Moss, Richard (2017年3月25日). “Roam free: A history of open-world gaming”. Ars Technica. 2017年10月6日閲覧。 “Amazingly, open-world games can be traced back to the days of mainframes?namely, to the 1976 text-only game Colossal Cave Adventure for the PDP-10. Adventure at its core wasn't much different to the GTAs, Elites, and Minecrafts of today: you could explore, freely, in any direction, and your only goals were to find treasure (which is scattered throughout the cave) and to escape with your life.”
Moss, Richard (2017年3月25日). “Roam free: A history of open-world gaming”. Ars Technica. 2017年10月6日閲覧。 “Colossal Cave Adventure was a direct inspiration on 1980 Atari 2600 game Adventure. Its open world may have been sparse and populated by little more than dragon-ducks and simple geometric shapes, but its relative vastness enabled players to imagine magnificent adventures of their own making.”
Mason, Graeme (2017年4月9日). “10 games that defined the ZX Spectrum”. Eurogamer. 2017年10月14日閲覧。 “Lords Of Midnight's wonderful storyline (inspired, unsurprisingly, by The Lord Of The Rings), open-world gameplay and elegant graphics were one thing - its seemingly effortless welding of the traditional adventure game to these features set a new standard for software that remains an amazing feat over 30 years later.”
Jankiewicz, Joshua (2016年7月22日). “Valhalla”. Hardcore Gaming 101. 2016年10月27日時点のオリジナルよりアーカイブ。2017年10月14日閲覧。 “Still, for a pre-King's Quest graphic adventure, Valhalla remains pretty unique with its open-world aspects. Being able to kill anyone and anything can be great fun, and seeing what weird things the NPCs will do on autopilot is strangely endearing.”
O'Connor, Alice (2015年1月15日). “Have You Played… Quarantine?”. 2017年10月14日閲覧。 “An open-world taxi game set in a hyperviolent dystopian futurecity, 1994's Quarantine is hugely exciting in my foggy memory.”
Jankiewicz, Joshua (2016年7月22日). “Valhalla”. Hardcore Gaming 101. 2016年10月27日時点のオリジナルよりアーカイブ。2017年10月14日閲覧。 “Still, for a pre-King's Quest graphic adventure, Valhalla remains pretty unique with its open-world aspects. Being able to kill anyone and anything can be great fun, and seeing what weird things the NPCs will do on autopilot is strangely endearing.”
