Despite some criticism going towards its steep learning curve and overall complexity, Dota 2 was praised for its rewarding gameplay, production quality, and faithfulness to its predecessor, with many considering it to be one of the greatest video games of all time. Since its release, it has been one of the most played games on Steam, with over a million concurrent players at its peak. The popularity of the game has led to official merchandise for it being produced, including apparel, accessories, and toys, as well as promotional tie-ins to other games and media. The game also allows for the community to create their own gamemodes, maps, and cosmetics, which are uploaded to the Steam Workshop. Valve have also developed two other games featuring the setting of Dota 2. The first, Artifact, is a digital collectible card game that released in November 2018, while the second, Dota Underlords, is a chess-like game derived from Dota Auto Chess, a popular community-created mod from within the game. Dota 2 has also been used in machine learning experiments, with a team of bots known as the OpenAI Five showing the capability to defeat professional players.
Gameplay
Dota 2 is a multiplayer online battle arena (MOBA) video game in which two teams of five players compete to collectively destroy a large structure defended by the opposing team known as the "Ancient", whilst defending their own. As in Defense of the Ancients, the game is controlled using standard real-time strategy controls, and is presented on a single map in a three-dimensional isometric perspective. Ten players each control one of the game's 117 playable characters, known as "heroes", with each having their own design, strengths, and weaknesses. Heroes are divided into two primary roles, known as the "carry" and "support". Carries, which are also called "cores", begin each match as weak and vulnerable, but are able to become more powerful later in the game, thus becoming able to "carry" their team to victory. Supports generally lack abilities that deal heavy damage, instead having ones with more functionality and utility that provide assistance for their carries, such as providing healing and other buffs. Players select their hero during a pre-game drafting phase, where they can also discuss potential strategies and hero matchups with their teammates. Heroes are removed from the drafting pool and become unavailable for all other players once one is selected, and can not be changed once the drafting phase is over.
All heroes have a basic damage-dealing attack, in addition to powerful abilities. Each hero has at least four abilities, all of which are unique, which are the primary method of fighting. Heroes begin each game with an experience level of one, only having access to one of their abilities, but are able to level up and become more powerful during the course of the game, up to a maximum level of 25. Whenever a hero gains an experience level, the player is able to unlock another of their abilities or improve one already learned. The most powerful ability for each hero is known as their "ultimate", which requires them to have an experience level of six in order to use. In order to prevent abilities from being used without consequence, a magic system in the game exists. Activating an ability costs a hero some of their "mana points", which slowly regenerates over time. Using an ability will also cause it to enter a cooldown phase, in which the ability can not be used again until a timer counts down to zero. All heroes have three attributes: strength, intelligence, and agility, which affect health points, mana points, and attack speed, respectively. Each hero has one primary attribute out of the three, which adds to their non-ability basic damage output when increased. Heroes also have an ability augmentation system known as "Talent Trees", which allow players further choices on how to develop their hero. If a hero runs out of health points and dies, they are removed from active play until a respawn timer counts down to zero, where they are then respawned in their base.
The two teams—known as the Radiant and Dire—occupy fortified bases in opposite corners of the map, which is divided in half by a crossable river and connected by three paths, which are referred to as "lanes". The lanes are guarded by defensive towers that attack any opposing unit who gets within its line of sight. A small group of weak computer-controlled creatures called "creeps" travel predefined paths along the lanes and attempt to attack any opposing heroes, creeps, and buildings in their way. Creeps periodically spawn throughout the game in groups from two buildings, called the "barracks", that exist in each lane and are located within the team's bases. The map is also permanently covered for both teams in fog of war, which prevents a team from seeing the opposing team's heroes and creeps if they are not directly in sight of themselves or an allied unit. The map also features a day-night cycle, with some hero abilities and other game mechanics being altered depending on the time of the cycle. Also present on the map are "neutral creeps" that are hostile to both teams, and reside in marked locations on the map known as "camps". Camps are located in the area between the lanes known as the "jungle", which both sides of the map have. Neutral creeps do not attack unless provoked, and will respawn over time if killed. The most powerful neutral creep is named "Roshan", who is a unique boss that may be defeated by either team to obtain special items, such as one that allows a one-time resurrection if the hero that holds it is killed. Roshan will respawn around ten minutes after being killed, and becomes progressively harder to kill as the match progresses over time. "Runes", which are special items that spawn in set positions on the map every two minutes, offer heroes various temporary, but powerful power-ups when collected.
