Visions of post-nuclear apocalypse have long been a popular setting for dystopian fiction, and one video game series that took advantage of such a setting celebrates its 20th anniversary this month. Fallout, created by Interplay Entertainment and currently developed and published by Bethesda Softworks, first arrived on computers on September 30, 1997.

The original title introduced the world following what’s known in-universe as the Great War, a devastating nuclear event that takes place in October 2077 that results in most major cities being destroyed over the course of just two hours. Society collapses completely shortly thereafter and surviving humans – ones who were not warped into ghouls or other monstrosities by the radiation – attempt to form small colonies and settlements throughout the nuclear wasteland. Some people were able to survive the Great War in fallout shelters known as “Vaults.” The first Fallout title begins in one of these Vaults, Vault 13, about 84 years after the war.

Fallout put players in control of their customizable Vault Dweller, who must leave the safety of their shelter and venture out into the wasteland after the Vault’s water chip, a computer device responsible for maintaining clean water, breaks. The Vault Dweller travels across the southern California desert seeking a replacement chip, and eventually is able to find it and save Vault 13. However, a greater threat looms in the form of Super Mutants – massive, hulking, mutated humans who were created by the use of the “Forced Evolutionary Virus.” The Super Mutants were created by a being known simply as the Master; the Vault Dweller is eventually able to defeat the Master and stop more Super Mutants from being created.

There are several ways that the player can experience a game over situation in Fallout – being unable to return to Vault 13 with a new water chip before the time limit expires, being unable to destroy the Master before the time limit expires, or by allowing the Super Mutants to find a military base and take control of it.

Interplay developed the original title after gaining the rights to create games using the GURPS (Generic Universal Role Playing System) system. GURPS later simply became the basis for Fallout’s SPECIAL character creation system, which has been used for all game entries since. The game was heavily inspired by the 1988 PC title Wasteland, which featured a similar setting, and is considered somewhat of a spiritual successor to that game.

Fallout received significant critical praise upon its 1997 release, winning several “RPG of the Year” awards from major gaming publications. It received a sequel a year later, featuring several improvements on the original system.

However, Interplay was eventually faced with the threat of bankruptcy and sold the rights to the Fallout franchise to Bethesda, who released Fallout 3 in 2008; the game brought what was previously a rather niche hardcore RPG series to a much wider audience by blending first-person shooting action with RPG elements. However, many fans of the original two titles have long resented the hard turn the gameplay style took when Bethesda took over development.

Since Fallout 3, Bethesda has kept the series going with Fallout: New Vegas in 2010 and Fallout 4 in 2015, plus the mobile title Fallout Shelter. With Fallout 4 heading to virtual reality headsets – allegedly by the end of 2017 – it’s clear that, though it’s a long way from Interplay’s original game, the Fallout series will continue pushing the limits.