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Deathmatch, also known as free-for-all, is a gameplay mode integrated into many shooter games, including first-person shooter (FPS), and real-time strategy (RTS) video games, where the goal is to kill (or "frag") the other players' characters as many times as possible. The deathmatch may end on a frag limit or a time limit, and the winner is the player that accumulated the greatest number of frags.
In a typical first-person shooter (FPS) deathmatch session, players connect individual computers together via a computer network in a peer-to-peer model or a client–server model, either locally or over the Internet. Each individual computer generates the first person view that the computer character sees in the virtual world, hence the player sees through the eyes of the computer character.
Players are able to control their characters and interact with the virtual world by using various controller systems. When using a PC, a typical example of a games control system would be the use of a mouse and keyboard combined. For example, the movement of the mouse could provide control of the players viewpoint from the character and the mouse buttons may be used for weapon trigger control. Certain keys on the keyboard would control movement around the virtual scenery and also often add possible additional functions. Games consoles however, use hand held 'control pads' which normally have a number of buttons and joysticks (or 'thumbsticks') which provide the same functions as the mouse and keyboard. Players often have the option to communicate with each other during the game by using microphones and speakers, headsets or by 'instant chat' messages if using a PC.
Every computer or console in the game renders the virtual world and characters in realtime sufficiently fast enough that the number of frames per second makes the visual simulation seem like standard full motion video or better. Manufacturers of games consoles use different hardware in their products which means that quality and performance of the games vary.
Deathmatches have different rules and goals depending on the game, but an example of a typical FPS-deathmatch session is where every player is versus every other player. The game begins with each player being spawned (starting) at random locations—picked from a fixed predefined set. Being spawned entails having the score, health, armor and equipment reset to default values which usually is 0 score, full (100%) health, no armour and a basic firearm and a melee weapon. After a session has commenced, arbitrary players may join and leave the game on an ad hoc basis.
In this context a player is a human operated character in the game or a character operated by a computer software AI—a bot (see Reaper bot for example). Both the human and computer operated character do have the same basic visual appearance but will in most modern games be able to select a skin which is an arbitrary graphics model but that operates on the same set of movements as the base model. A human player's character and computer bot's character features the same set of physical properties, initial health, initial armour, weapon capabilities, the same available character maneuvers and speed—i.e. they are equally matched except for the actual controlling part. For a novice player the difference (i.e. experience, not taking into account the actual skill) between a human opponent and a computer controlled opponent may be near nil, however for a skilled player the lack of human intelligence is usually easily noticed in most bot implementations; regardless of the actual skill of the bot—which lack of intelligence can be at least somewhat compensated for in terms of e.g. extreme (superhuman) accuracy and aim. However, some systems deliberately inform the player when inspecting the score list which player(s) are bots and which are human (e.g. OpenArena). In the event that the player is aware of the nature of the opponent it will affect the cognitive process of the player regardless of the player's skill. 
All normal maps will contain various power-ups; i.e. extra health, armor, ammunition and other (more powerful than default) weapons. Once collected by a player the power-up will respawn after a defined time at the same location, the time for an item to respawn depends upon the game mode and the type of the item. In some deathmatch modes power-ups will not respawn at all. Certain power-ups are especially powerful, which can often lead to the game rotating around controlling power-ups—i.e. assuming ceteris paribus, the player who controls the [most powerful] power-ups (namely collect the item most often) is the one that will have the best potential for making the best score.
The goal for each player is killing the other players by any means possible which counts as a frag, either by direct assault or manipulating the map, the latter counts as a frag in some games, some not; in either case—to attain the highest score—this process should be repeated as many times as possible, with each iteration performed as quickly as possible. The session may have a time limit, a frag limit, or no limit at all. If there is a limit then the player with the most frags will eventually win when the session ends.
The health variable will determine if a player is wounded; however, a wounded player does not entail reduced mobility or functionality in most games, and in most games a player will not bleed to death. A player will die when the health value reaches equal to or less than 0, if the value is reduced to a very low negative value, the result may be gibbing depending upon the game. In most games, when a player dies (i.e. is fragged), the player will lose all equipment gained and the screen will continue to display the visible (still animated) scene that the player normally sees, and the score list is usually displayed—the frags. The display does not go black when the player dies. Usually the player can choose to instantly respawn or remain dead.
The armor variable affects the health variable by reducing the damage taken, the reduction in health is in concept inversely proportional to the value of the armor times the actual damage caused; with the obvious differences in various implementations. Some games may account for the location of the body injured when the damage is deduced, while many—especially older implementations—do not. In most games, no amount of armor causes any reduced mobility—i.e. is never experienced as a weight issue by the player.
Newtonian physics are often only somewhat accurately simulated, common in many games is the ability of the player to modify the player's own vector to some degree while airborne, e.g. by retarding a forward airborne flight by moving backwards, or even jumping around a corner. Other notable concepts derived from the physics of FPS game engines are i.a. at least bunny-hopping, strafe-jumping and rocket-jumping—in all of which the player exploits the particular characteristics of the physics engine in question to obtain a high speed and/or height, or other attribute(s); e.g. with rocket-jumping the player will jump and fire at rocket at the floor area immediately under the feet of the same player, which will cause the player to jump higher compared to a regular jump as a result of the rocket blast (at the obvious expense of the health variable being somewhat reduced from self-inflicted injury). The types of techniques available and how the techniques may be performed by the player differs from the physics implementation as is as such also game dependent.
The lost equipment (usually not including the armor) of a dead player can usually be picked up by any player (even the fragged player, respawned) who gets to it first.
Modern implementations allow for new players to join after the game has started, the maximum number of players that can join is arbitrary for each game, map and rules and can be selected by the server. Some maps are suitable for small numbers of players, some are suitable for larger numbers.
If the session does have a frag or time limit a new session will start briefly after the current session has been concluded, during the respite the players will be allowed to observe the score list, chat and will usually see an animated pseudo overview display of the map as background for the score list. Some games have a system to allow each player to announce they are now ready to begin the new session, some do not. The new sessions might be on a different map—based on a map list kept on the server—or it might always be on the same map if there is no such rotating map list.
Common in many games is some form of message broadcast and private message system; the broadcast message system announces public events, e.g. if a player died it will often be informed who died and how, if fragged, then often by what weapon; the same system will also often announce if a player joins or leaves the game, and may announce how many frags are left in total and other important messages, including errors or warnings from the game; instant text messages from other players are also displayed with this system. The private message system, in contrast, only prints messages for individual players, e.g. if player A picks up a weapon, player A will get a message to confirm that the weapon was picked up.
Most modern deathmatch games features a high level of graphic violence; a normal modern implementation will contain high quality human characters being killed, e.g. moderate amounts of blood, screams of pain and death, exploding bodies with associated gibs are common. Some games feature a way to disable and/or reduce the level of gore. However, the setting of the game is usually that of a fictional world, the player may resurrect in the form of mentioned respawning and the characters will usually have superhuman abilities, e.g. able to tolerate numerous point blank hits from a machine gun directly to the head without any armour, jumping extreme inhuman distances and falling extreme distances to mention a few things. These factors together may make the player experience the game less real as the game contains highly unreal and unrealistic elements.
The description depicts a typical deathmatch based on major titles such as Quake, Doom, Unreal Tournament and others, the purpose served is to give a basic idea of the concept; however, given the many variations that exist and the manner that options and rules may be manipulated literally everything mentioned could be varied to a greater or lesser extent in other games.
The origin of the term deathmatch in the context of video games is disputed, especially as it is not well-defined; for pointers, the term was coined by game designer John Romero while he and lead programmer John Carmack were developing the LAN multiplayer mode for the video game Doom. World Heroes 2, also developed and released in the early 1990s, is another early use of the term. However, the latter's usage was different as it referred to the players' environment (arenas which housed dangerous hazards) rather than to the game itself. Both of these claims are controversial as the term's common definition as used by gamers (to describe a video game match in which players kill each other over and over, respawning after each time they die) predates both titles by over a decade. Romero commented on the birth of the FPS deathmatch:
According to Romero, the deathmatch concept was inspired by fighting games. At id Software, the team frequently played Street Fighter II, Fatal Fury and Art of Fighting during breaks, while developing elaborate rules involving trash-talk and smashing furniture or tech. Romero stated that "what we were doing was something that invented deathmatch" and that "Japanese fighting games fueled the creative impulse to create deathmatch in our shooters." 
Games that had such gameplay features beforehand did not use the term, but later it gained mainstream popularity with the Quake and Unreal Tournament series of games. MIDI Maze was a multiplayer first-person shooter for the Atari ST, released in 1987, which has also been suggested as the first example of deathmatch before the term was used.  Sega's 1988 third-person shooter arcade game Last Survivor featured eight-player deathmatch. 
Some games give a different name to these types of matches, while still using the same underlying concept. For example, in Perfect Dark, the name "Combat Simulator" is used and in Halo, deathmatch is known as "Slayer".
An early example of a deathmatch mode in a first-person shooter was Taito's 1992 video game Gun Buster. It allowed two-player cooperative gameplay for the mission mode, and featured an early deathmatch mode, where either two players could compete against each other or up to four players could compete in a team deathmatch, consisting of two teams with two players each competing against each other. 
It has been suggested that in 1983, Drew Major and Kyle Powell probably played the world's first deathmatch with Snipes[ citation needed], a text-mode game that was later credited with being the inspiration behind Novell NetWare, although multiplayer games spread across multiple screens predate that title by at least 9 years in the form of Spasim and Maze War.
Early evidence of the term's application to graphical video games exists. On August 6, 1982, Intellivision game developers Russ Haft and Steve Montero challenged each other to a game of Bi-Planes, a 1981 Intellivision release in which multiple players control fighter planes with the primary purpose of repeatedly killing each other until a limit is reached. Once killed, a player would be respawned in a fixed location, enjoying a short period of protection from attacks. The contest was referred to, at that time, as a deathmatch. 
In a Team Deathmatch, the players are organized into two or more teams, with each team having its own frag count. Friendly fire may or may not cause damage, depending on the game and the rules used — if it does, players that kill a teammate (called a team kill) usually decrease their own score and the team's score by one point; in certain games, they may also themselves be killed as punishment, and/or may be removed from the game for repeat offenses. The team with the highest frag-count at the end wins.
In a last man standing deathmatch (or a battle royale game), players start with a certain number of lives (or just one, in the case of battle royale games), and lose these as they die. Players who run out of lives are eliminated for the rest of the match, and the winner is the last and only player with at least one life. See the "Fundamental changes" section in the "Last Man Standing" article for more insight.
Any arbitrary multiplayer game with the goal for each player to kill every other player(s) as many times as possible can be considered to be a form of deathmatch. In real time strategy games, deathmatch can refer to a game mode where all players begin their empires with large amounts of resources. This saves them the time of accumulation and lets hostilities commence much faster and with greater force. Destroying all the enemies is the only way to win, while in other modes some other victory conditions may be used (king of the hill, building a wonder...)
Within months, these rules were modified into "Deathmatch 2.0" rules (included in Doom v1.2 patch). These rules were optional, the administrator of the game could decide on using DM 1.0 or DM 2.0 rules.
The changes were:
Notable power-ups that are featured in most consecutive games include the soul spheres. Although the name and/or graphics may be different in other games the concept and feature of the power-up remains the same in other games.
Notable power-ups that are featured in most consecutive games are i.a. the quad damage. Although the name and/or graphics may be different in other games the concept and feature of the power-up remains the same in other games.
This game's approach to combat achievements tracking is different from Unreal Tournament. In deathmatch, the player might be rewarded with awards for the following tricks:
The Last Man Standing (LMS) version of deathmatch is fundamentally different from deathmatch. In deathmatch, it does not matter how many times the player dies, only how many times the player kills. In LMS, it is the exact opposite — the important task is "not to die". Because of this, two activities that are not specifically addressed in deathmatch have to be controlled in LMS.