Health is a gameplay mechanism, used in various forms of role-playing and video games to give a value to characters, enemies, NPCs, and objects related to death and/or the defeat of the player, enemies, or NPCs, or the destruction and/or ruination of the object. This value can either be numerical, semi-numerical as in hit points, or arbitrary as in a life bar.

Hit points

Hit points, also known as health points, life points, HP, damage points, life bar, or just health (and countless other synonyms), are points used to determine a character's health and show how much damage attacks deal in role-playing games, computer and video games and wargames. These terms are typically shortened to two letter acronyms such as HP or DP.

History

Hit points are such an integral part of almost all games that depict violent conflict that it is hard to imagine that they were invented. In an 2004 interview with Allen Rausch of GameSpy, David Arneson talks about how the origins of hit points can be found at the very beginning of role-playing games. While Arneson and Gary Gygax were adapting the medieval war game Chainmail to a fantasy setting, a process that would lead to the game Blackmoor and eventually Dungeons & Dragons, the two men saw that the emphasis of the gameplay was moving from large armies to small groups of heroes and eventually to the identification of one player and one character that is so essential to role-playing as it was originally conceived. Players became attached to their heroes and did not want them to die every time they lost a die roll. In war games, a player is willing to have combat resolution for individual figures be a binary affair - either a figure survives and stays on the table or is killed and taken off the table. The player has dozens or hundreds of figures in his army or navy; the loss of any number of them does not end the game. But when, as in a role playing game, a player only has one character, that character's death is not so easily acceptable. Hit points, a concept which Arneson says he borrowed from a Civil War game called "Ironclads" he had developed earlier, offer a resolution of the tension between not wanting a character's survival to be guaranteed - in which case a role-playing game ceases to be a game and becomes an impromptu story-telling session - and not wanting the only negative outcome of a battle to be death. With hit points, players could experience the exciting tension of having their characters damaged by monsters but still survive.

Use in role-playing games

In the Dungeons & Dragons fantasy role-playing game and D&D-derived games, player characters' hit points are determined by character level, and monsters' hit points are determined by a mechanism similar to character levels called "Hit Dice". Characters with high constitution will have an advantage when hit points are assigned.

In some games, hit points are determined by the type and strength of the attack, and when an attack succeeds hit points are deducted from the target's remaining supply. In most games using this system, when a character reaches zero hit points, the character dies, becomes unconscious, or is destroyed. One limitation of hit points is that in reality people typically lose combat effectiveness as they are hurt. However, conveying that realistically has proven very difficult for the gaming industry, particularly with "living" characters; robots or vehicles, that also have Hit Points, can register damage as systems going offline.

Use in video games

Screenshot of a battle in Final Fantasy Tactics Advance. The character's HP can be seen in the lower left corner in blue lettering.

Although many video games use a life bar to display a character's health and how close the player is to failure (death, being knocked out, et cetera), many wargames, computer role-playing games, and combat-oriented video games instead use numbers to show more accurately the amount of damage an object or player in the game can take before becoming ineffective. The use of hit points instead of more realistic, yet violent, gauges of "health" may help a game get a lower ESRB rating, as showing blood often raises the ESRB rating.

HP may also be displayed with icons instead of numbers. For instance, Super Mario Bros. 2 uses small red icons (in 16-bit versions of the game, they're changed to hearts) in the top left corner to designate how many hitpoints the player has remaining, and Dracula for the Sega Genesis uses small flasks of liquid. The Legend of Zelda series are other good examples of this method. In such games, often some weak attacks against the player will take only a fraction of a heart (typically one-quarter or one-half) and stronger attacks may take many whole hearts at once.

In more recent games, characters typically slouch over and breathe heavily (as a result of low HP) when left on idle. They may also have impaired mobility, staggering and stumbling as in the Max Payne series.

Some games use a life bar in order to graphically represent hit points remaining, such as the Pokémon series (where enemy monsters' HP are shown only as a bar) and various fighting games. In some cases, writers on such games, such as the Tekken series, will refer to the hit points of a damaging move, instead of a more common percentage of life bar description.

Other games, such as Deus Ex, show an image of a human body, which is all green to begin with. As the player takes damage, the respective region of the body turns yellow, orange, red, and eventually disappears altogether. For the head and torso, this is fatal. Stubbs the Zombie also uses a picture of Stubbs's body to represent how much much life is remaining, although this is unlike Deus Ex in that the life drains from head to toe, with no special attention to where the damage is sustained.

Some games give bonuses or enrichments to players if they have or attain a specific amount of HP. Final Fantasy VII's secret "All Lucky 7's" feature (which is also known as "7777 Fever" by fans) causes a character that has 7777 HP to start attacking enemies automatically for 64 hits, dealing 7777 points of damage with each hit. After 64 consecutive hits have been dealt, each manual attack (physical or magical) by the character will cause 7777 points of damage, until the character's HP changes. However, when the battle is finished, that character will have only 1 HP remaining. This is to ensure that the player can't use "All Lucky 7's" in every battle.

Special uses

Two special uses of HP involve zero and negative HP. They are two special conditions for certain role-playing games that allows for special actions that must be done in order to disrupt normal battle rules.

Zero HPWhen Mallow uses his "Psychopath" ability on Dry Bones, it's reported that Dry Bones has 0 HP but is still alive (or "undead" in the case of Dry Bones).

Zero HP is related to some cases when an enemy's HP is visible, it's reported to be zero. In this case, some enemies in games are invulnerable, because their HP is 0 to begin with and its maximum HP is 0. Since the enemy isn't dead at 0 HP, doing more damage will not do anything, and healing it will not do anything either because it's at its maximum HP.

In a programming sense, the enemy may not have a case where it is defeated based on HP, or that it has a really high HP value (such as 216 or 232) and it simply gets completely healed every round. The latter may be used more often, as this simply complies with normal combat engine rules.Examples

In Super Mario RPG: Legend of the Seven Stars, the "Dry Bones" creature is an enemy that has zero HP. Both it and the upgraded "Vomer" counterpart are immune to regular attacks, but they are defeated instantly by any special attack. This is probably due to their being undead enemies.

In EarthBound, Giygas in its third form can't be defeated by simply attacking. Despite when Paula uses her Pray command and the result is damages in the hundreds of thousands, this is probably just to show hyperbolically that when other people pray for the characters, Giygas can't withstand it. However, hacking into the ROM of EarthBound shows that Giygas actually has 65535 HP and every turn it is healed.

In Breath of Fire III, when battling Balio and Sunder for the first time, they can't be defeated no matter what.

In various Final Fantasy games, characters inflicted with the zombie status effect will have zero HP. Games in this family have also carried the characteristic of having undead characters and enemies taking damage due to restorative items and spells.

In Metal Gear Solid 3: Snake Eater, The Sorrow is shown to have zero hit points. This is due to the fact that he is already dead. He is instead beaten by walking past the ghosts of every human Snake has killed.

Negative HP

In some games, a character or monster can be "alive" although their HP are below zero. Usually, the character is unable to do anything; they are considered to be unconscious or similarly inactive. In the case with enemies, some of them must be brought down to a negative HP level before they can be defeated. Negative HP are most often found in role-playing games.Examples

A Player Character in some editions of Dungeons & Dragons with HP of zero is not dead; they are knocked unconscious at zero HP. In the range of -1 and -9, they are considered to be mortally wounded and dying, and their HP will steadily drop unless stabilized (naturally, or through healing). At -10, the character dies. Note, however, that a player who takes 50 points of damage or more in one blow (according to the "Death from Massive Damage" alternate rule), must make a saving throw based on the amount of damage even if they are not reduced to -10; failure of this check causes the player to die regardless of remaining HP. The exact value of the "Massive Damage" amount is based on the size category or total hit points of the character/monster being attacked. Notably, in some editions of Dungeons and Dragons, once a character is reduced to zero hitpoints, they perish.

Similarly, in Paranoia, when using the d20 version, receiving 20 or more points of damage in one blow (without falling to -10 HP) forces the player to make a saving throw against (amount of damage - 5). Failing this saving throw means that the player is vaporized (although due to the nature of the game, this is a minor inconvenience in most instances).

In the Starship Troopers RPG, a character can be brought to a negative HP level and yet still be revived by a field medic.

In Breath of Fire during boss fights, the boss continues to live and fight for a certain finite HP limit although its designated life bar has depleted.

Negative HP is also seen in the FPS game Doom 3 if the player happens to die from a highly damaging event (being at the center of an explosion or being crushed), in which the life display reads a negative number, though this is probably just for a comic exaggeration. In the Quake games, negative HP can tell the player how much damage the player character took. Between 0 and -40 the player model is intact and in one of several pre-made death poses; beyond -40, the player model is gibbed.

A unique "rolling HP" system is used in the second and third games of the Earthbound series. Similar to a slot machine, HP is represented by 3 rows of numbers that scroll positively or negatively depending on the situation. When a character receives "mortal damage" (when the attack would knock his or hers hp to 0 or less), he/she does not die instantly. Rather, the row of the HP will start rolling down to what the remaining HP should be. If the character can win the battle before then, their HP will be whatever the number the row was at the end of the fight. This factor is extremely important in Mother 3, where players' HP would frequently reach very very low negative numbers, such as -346, during major fights, which added to the tension of winning battles quickly.

In the Star Wars: Knights of the Old Republic games by BioWare (and then by Obsidian), a character that has been knocked out will often be displayed with a negative amount of health, if they have taken more damage that is necessary to knock them out.

In EverQuest, a player is knocked out cold at zero hit points, and is killed below -9.

Damage ranks

Some systems have eliminated the use of HP, preferring instead to reflect damage through its effect on a character's ability to perform by reducing the effectiveness of a character's attributes, skills, personality, and other abilities, allowing a fighter and a wizard to have roughly equal staying power during a fight. In Truth & Justice, for example, conflicts result in the accumulation of either "failure ranks" (which recover at the end of the contest) or "damage ranks" (which may take longer to heal). Each point of either type means that the loser must choose a stat to downgrade by one rank. While this type of system is more realistic in the effect injury/damage has on a player, enemy, NPC, or object, it can be annoying to the player if his or her character loses capabilities every time his/her character takes a hit.

Life bar

Screenshot of Metal Gear Solid. The life bar can be seen in the upper left corner. Notice that there is only a small amount of blue remaining, which probably means that Snake is close to defeat.

A health bar is used in many video games to display a character's health and how close the player is to failure (death, being knocked out, etc). A typical life bar is a horizontal rectangle which begins full of colour. If damage is taken or mistakes are made, the coloured area gradually reduces. In some game cheats, the bar can be set to unlimited, which means the full color remains the same even when one takes a hit.

There are many variations on the life bar:

In the Sonic the Hedgehog series, the player collects rings, which are used as a life indicator. They are shown as numbers at the upper left side of the screen. When an enemy hits the main character, Sonic, his rings scatter around. If the player is fast enough, he can catch some of the scattered rings. If Sonic loses his rings, he is vulnerable and will lose a life when an enemy hits him. When the player collects 100 rings together, Sonic gains an extra life.

In Street Fighter and other fighting games, the bar doesn't instantly decrease when damage is taken. Instead, an area representing the damage is marked, and the health lost quickly drains away. This is useful in assessing the amount of damage caused by a specific attack.

Some games use an incremental bar, composed of many smaller bars. Each attack will remove a certain number of these bars. This system is used in the Mega Man series.

In Mario's 3D games, the health bar appears in a circle but is based on the game's theme. Going above water for air or collecting coins refills it. It will only appear if Mario is in the water or is not at full health.

In many rhythm games, the health bar starts out only partially full, and can be filled by successful play. The game typically ends when the health bar is fully depleted. In games such as beatmania, Donkey Konga, and Taiko: Drum Master, the health bar must be above a certain percentage by the end of the song to pass it (often around 75%). In other games, including Dance Dance Revolution, GuitarFreaks, Pump It Up, FreQuency, and Guitar Hero (in this case, a "Rock Meter"), the health bar must simply be above 0% to continue playing.

In Osu! Tatakae! Ouendan and the localized version of the game, Elite Beat Agents, the health bar (called the Elite-O-Meter) starts out full and gradually decreases as time goes on, while playing well refills it from the draining of time. The player must keep it above zero in order to continue playing, and above a certain percentage of the meter at breaks in order to get better results on the top screen.

Some video games also feature a recharging health bar (sometimes depicted as an energy shield). In these games, the player character can't typically take as much damage as a player with a traditional life bar, but health regenerates over time (Usually when the player is hiding from enemy fire). Notable examples of this are the Halo series, Call of Duty 2, 3, and 4, Destroy All Humans! and Gears of War.

In Pac-Man World and it's sequels, the health bar is the Pac-Man symbol split up into three. Pac-Man will lose a life when he gets hit a fourth time.

Gears of War makes use of a cog-shaped icon called the "Crimson Omen." If the player takes a certain amount of damage in a certain amount of time, a red cog begins to appear on the screen, becoming more defined, and then filling with blood. When it is completely full, a red skull appears in the middle, in most cases signifying that the player has died (in two-player co-operative games, however, the player may not have been killed outright; in those instances, the other player can revive the incapacitated player, provided, of course, that they themselves do not become incapacitated; if that happens, then both players die, and the mission fails).

In a similar vein, Call of Duty does not have a health bar, instead choosing to start by showing where the damage is coming from, then, if enough damage is taken quickly enough, the edges of the screen begin turning red. If too much damage is taken in too short an interval, the player dies, and the mission fails.

In Grand Theft Auto III and Grand Theft Auto: Vice City, numbers were used to designate how much Health a player had left. They also added an armor number, for protection. The series used this in all of their games up to Grand Theft Auto: San Andreas, when the numbers were replaced with a health bar.

In order to be more immersive, some games do away with the health bar (and other on-screen displays) completely and try to present a player's health in other ways, such as showing the player character limping or displaying visible wounds when they are injured. A particularly notorious example of this features in the first-person shooter Jurassic Park: Trespasser, in which a tattoo on the female player character's breast would become bloody if damage has been taken. In the Resident Evil video games, health is shown both with the player character limping and pressing his/her wounds in pain, and with an EKG display in the inventory screen. Peter Jackson's King Kong: The Official Game of the Movie has no life bar; instead, the screen flashes red, and vision becomes blurred (more damage designated by a deeper red coloration). In more recent games, characters typically slouch over and breathe heavily (as a result of low health) when left on idle.

In a large number of games, if the player's health is almost empty ('critical'), it may flash or give some other warning indication to reflect the severity of the damage incurred. In the Legend of Zelda games, a continual beeping sound plays when the player falls to a critically low number of hearts. In the Call of Duty series, blood seeps onto the screen and the player character can be heard groaning in pain.

In Tak and the Power of Juju, the health meter is represented as the feather in Tak's hair. This feather is typically yellow, but as Tak takes damage, a percentage readout appears on the top of the screen and the feather's tip turns purple. When the feather turns completely purple, Tak faints.

In Grand Theft Auto: San Andreas, the length of the health bar (and the amount of damage the player can take) increases to the maximum upon the completion of the 'Ambulance' missions; alternatively, the health bar's length increases gradually with the player's average lifespan. Likewise, the armour bar increases upon completion of the Police 'Vigilante' missions.

Icon based health

Icon based health tends to unite both hit points and a life bar, where the value is arbitrary, but can be counted.

For example, in the video game series The Legend of Zelda, the main character's health is represented as small hearts, located near the top of the screen. While the number of hearts can be counted, the amount of hearts lost can vary depending on how strong the attack is. One attack may take a whole heart, and another attack may only take a half of a heart. A further example is Super Mario Bros. 2, in which the game uses small red icons (in 16-bit versions of the game, they're changed to hearts) in the top left corner to designate how many hit points the player has remaining. Icon-based health combines the best attributes of hit points and life bars; not only do they show precisely how much health a character has remaining, they also make it easy to find a rough estimate of how many hits one can take.

Percentage meter

In the Super Smash Bros. series, instead of health bars featured in most fighting games, percentage meters are used. When attacking an opponent or being attacked by an opponent, the percentage meter rises based on the damage inflicted; as the percentage meter increases, the character gradually becomes easier to knock away with strong attacks, possibly getting knocked out of the arena.