Mod (video gaming) in the context of Defense of the Ancients

DayZ is a multiplayer online survival video game developed and published by Bohemia Interactive. It is the standalone game based on the mod of the same name for Arma 2. Following a five-year-long early access period for Windows, the game was officially released in December 2018, and was released for the Xbox One and PlayStation 4 in 2019.

The game places the player in multiple fictional countries, where a mysterious plague has turned most of the population into violent "infected". As a survivor, the player must scavenge the world for food, water, weapons, and medicine, while killing or avoiding the infected, and killing, avoiding, or cooperating with other players in an effort to survive the outbreak.

Dota 2 is a 2013 multiplayer online battle arena (MOBA) video game by Valve. The game is a sequel to Defense of the Ancients (DotA), a community-created mod for Blizzard Entertainment's Warcraft III: Reign of Chaos. Dota 2 is played in matches between two teams of five players, with each team occupying and defending their own separate base on the map. Each of the ten players independently controls a character known as a hero that has unique abilities and differing styles of play. During a match, players collect experience points (XP) and items for their heroes to defeat the opposing team's heroes in player versus player (PvP) combat. A team wins by being the first to destroy the other team's Ancient, a large durable structure located in the center of each base.

Development of Dota 2 began in 2009 when IceFrog, lead designer of Defense of the Ancients, was hired by Valve to design a standalone remake in the Source game engine. It was released for Windows, OS X, and Linux via the digital distribution platform Steam in July 2013, following a Windows-only open beta phase that began two years prior. Dota 2 is fully free-to-play with no heroes or any other gameplay element needing to be bought or otherwise unlocked. Valve supports the game as a service, selling loot boxes and a battle pass subscription system called Dota Plus that offer non-gameplay altering virtual goods in return, such as hero cosmetics and audio replacement packs. The game was ported to the Source 2 engine in 2015, making it the first game to use it.

A battle royale game is an online multiplayer video game genre that blends last-man-standing gameplay with the survival, exploration, and scavenging elements of a survival game. Battle royale games involve dozens to hundreds of players, who start with minimal equipment and then must eliminate all other opponents while avoiding being trapped outside a shrinking "safe area", with the winner being the last player or team alive.

The name for the genre is taken from the 2000 Japanese film Battle Royale, itself based on the novel of the same name, which presents a similar theme of a last-man-standing competition in a shrinking play zone. The genre's origins arose from mods for large-scale online survival games like Minecraft and Arma 2 in the early 2010s. By the end of the decade, the genre became a cultural phenomenon, with standalone games such as PUBG: Battlegrounds (2017), Fortnite Battle Royale (2017), Apex Legends (2019) and Call of Duty: Warzone (2020) each having received tens of millions of players within months of their releases.

Bohemia Interactive a.s. is a Czech video game developer and publisher based in Prague. The company focuses on creating military simulation games such as Operation Flashpoint: Cold War Crisis and the Arma series. It is also known for having worked on a game conversion of the DayZ mod created for Arma 2.

Founded by Marek Španěl in May 1999, the studio released its first game in 2001, a military shooter titled Operation Flashpoint: Cold War Crisis, which received critical acclaim and brought recognition for the studio. Following Operation Flashpoint was a series of downturns, such as porting the game to Xbox, which led to financial losses and the development of a sequel later abandoned by the publisher Codemasters. The studio fell into financial troubles until the United States Marine Corps employed the studio to create simulation games to train soldiers. A new division called Bohemia Interactive Simulations was created, and later spun off and became a standalone business entity. Following Codemasters' decision of not supporting the studio, Bohemia Interactive decided to develop a spiritual successor to Cold War Crisis titled Arma: Armed Assault. It was both a critical and financial success, spawning a number of sequels. Smaller projects such as Take On Helicopters were also released.

DayZ is a multiplayer open world survival third-person shooter modification designed by Dean Hall for the 2009 tactical shooter video game Arma 2 and its 2010 expansion pack, Arma 2: Operation Arrowhead. The mod places the player in the fictional post-Soviet state of Chernarus, where a mysterious plague has infected most of the population, turning people into violent zombies. As a survivor with limited resources, the player must scavenge the world for supplies such as food, water, weapons and medicine, while killing or avoiding both zombies and other players, and sometimes non-playable characters, in an effort to survive the zombie apocalypse.

DayZ has been praised for its innovative design elements. The mod reached one million players in its first four months on August 6, 2012, with hundreds of thousands of people purchasing Arma 2 just to play it. In response to its popularity, Bohemia Interactive made a standalone game based on the mod. The mod itself remains in continued development by its community.