Oxygen Meter

Somewhere inbetween Super Drowning Skills and Super Not Drowning Skills lies the Oxygen Meter, which indicates the Player Character's capacity to hold his breath. If the Oxygen Meter depletes, one of two things will happen: instant death by asphyxiation, or the player character's actual health will begin to drain.

In water levels, there will often be designated stops that allow for the oxygen meter to be refilled, such as ceiling vents that allow you to resurface and breathe or bubbles that pop up in certain places to automatically refill the meter.

Frustratingly, your oxygen meter is sometimes invisible yet still just as real and waiting to bite you; this is most likely to happen in a first person shooter. This is probably just because the interface is already full and they don't want to waste space on something not even used in most levels... and nobody came up with the idea of making it only visible when in use.

An occasional alternative to the Oxygen Meter is to allow only for a finite amount of time underwater before the player character automatically floats back to the surface unharmed -- however this also places a restriction on level design, to avoid the player getting stuck should their "swim timer" run out in the middle of, say, an underwater tunnel or cavern with no air on the surface.

A third way, of course, is to just prohibit underwater travel entirely -- either by limiting swimming mechanics to the water's surface (such as in Bully), using Super Drowning Skills, or by simply not allowing the player to interact with deep water in the first place. (Sure, you can still splash around in puddles and knee-high streams, but to go jump in a lake? Are you crazy?)

Characters with Super Not Drowning Skills, by definition, rarely have need of an Oxygen Meter.


 * The Elder Scrolls series games Morrowind and Oblivion have "Breath" meters; if the breath meter empties, the player's health begins to drain rapidly. Can be circumvented using a Water Breathing spell or playing as the Argonian race.
 * Fallout 3 and Fallout New Vegas, which use the same engine, inherit this effect from Oblivion as well. It drains worryingly quickly, followed by massive health loss. Although a character in New Vegas can gain Super Not Drowning Skills with, again based on the very same effect as Water Breathing in Oblivion.
 * An interesting variation on this is that the meter is more and more forgiving as you increase your Endurance attribute.
 * The more recent 3D Super Mario Bros games. The original Super Mario 64 made the odd decision of using the health meter in lieu of a separate oxygen meter, while still allowing you to catch your breath when surfacing, which basically meant that you could refill your health for free by swimming around at the surface of any deep body of water, or continue holding your breath as long as you gathered coins (which healed your life meter). Super Mario Sunshine and both Galaxy games use a separate oxygen meter (though coins still refill it when underwater, and in Sunshine, it basically replaces your health meter while you're underwater.)
 * The Ty the Tasmanian Tiger games use the Mario 64 variant, with exactly the same consequences.
 * The oxygen meters in Super Mario Sunshine, Super Mario Galaxy and Super Mario Galaxy 2 can be apparently refilled by collecting coins. More interestingly, the Bee Mario form in the latter can fly longer by collecting coins in mid air to refill the flight meter. How that works is mentioned, but not quite explained.
 * Grand Theft Auto San Andreas. This was a departure from the rest of the series, as previous games gave the player Super Drowning Skills.
 * The game after this, Grand Theft Auto IV, kept the ability to swim but restricts it to the surface, so there's no meter.
 * Grand Theft Auto Vice City Stories also restricted it to the surface, but added a stamina meter which works exactly as an Oxygen Meter; when it runs out, you're screwed.
 * The ''Metal Gear Solid' series.
 * Many James Bond first person shooters.
 * American McGee's Alice has this meter for underwater levels where you don't have a shell. Annoying in that the meter is not visible, so you must gauge by bubbles when you're almost out of air. Doubly annoying in that once your health begins to decline, you are given absolutely no time to find an air source to stop yourself from dying.
 * In the Half-Life series, your hazardous environment suit provides you oxygen for a limited time. Oddly, the same meter that powers your sprint ability and flashlight is used for this in the second game. When you run out of air, your health starts dropping, but you can refill the health that you lost from drowning by coming up for air.
 * Health lost to drowning being replenished by coming up and a line from the first game's tutorial sequence suggests that when you go underwater in the first game or the suit's auxiliary power runs out in the second, Gordon is merely holding his breath; when health starts dropping, it's a sign that he used up the air in his lungs and what we see as his health actually represents his blood oxygen levels in this case. Just like in real life, staying underwater kills him because he holds his breath for so long he passes out from lack of oxygen - which is indirectly fatal when it happens underwater, especially if no one's around to pull a comatose scientist and his who-knows-how-heavy Powered Armor out of the dip. Still doesn't explain how he runs out of air so quick; maybe the suit's weight makes him have to exert more force to move underwater, using up air faster than normal. On the other hand, he IS a mere scientist, not a soldier or hobby swimmer.
 * The second game's auxiliary power supplying him oxygen can be explained away by his suit using that electricity to electrolyse oxygen from the water as he swims. Once that runs out... it's back to good old lungs.
 * In the first Far Cry your Sprint Meter doubled as a Oxygen meter.
 * In Shadow of the Colossus, your stamina meter doubled as an oxygen meter. If it ran out, you would simply let go of whatever you were holding and return to the surface.
 * Because the two are the same, it makes it rather odd when the main character is panting and gasping while completely submerged in the water.
 * The 3D The Legend of Zelda games use both varieties. Diving while swimming normally only lasts for a few seconds before Link resurfaces. Equipping the Iron Boots lets Link stay underwater longer, in which case a timer based on how much health you have appeared. Unless you also equipped the Zora Tunic, which lets you breathe underwater. These two items, of course, are often used in water dungeons (and the need to switch between the normal boots and the iron boots was part of what made the Water Temple in Ocarina of Time such a Scrappy Level.) The Twilight Princess version is a bit better off since it's easier to switch the boots on and off. Being able to use items other than the hookshot underwater probably helped as well.
 * The Wind Waker did not have any underwater breathing, but did have a stamina bar to prevent you from swimming from island to island.
 * Skyward Sword has an oxygen meter as well, which is barely of note until you get the Water Dragon's Scale (Link automatically floats upward when he's not focused on swimming). Staying underwater depletes it, using your spinning attack depletes it faster, and whatever you do, don't inhale the colorful bubbles! There is a potion that slows the rate Link consumes oxygen, however.
 * Duke Nukem Time To Kill deviated from the first-person variant by actually providing the player with a LCD heads-up oxygen meter. There was the added caveat, however, of no scuba gear to be found.
 * The first Ratchet and Clank game.
 * Fortunately, Ratchet gains an oxygen mask about halfway through the first game-and unlike most of his weapons and items the mask makes it to every subsequent game, making it a non-issue for the rest of the series.
 * Two-dimensional Sonic the Hedgehog games give the character an invisible oxygen meter, with a countdown from 5 to 1 followed by automatic death when it runs out.
 * Complete with the dreaded countdown music.
 * To be fair though, it did take 2-3 real world seconds for each tick of the countdown, and most underwater sections had those mysteriously convenient sources of Sonic-sized (presumably so you could also get your torso inside and equalize pressure) breathable-air bubbles about every 30 seconds of distance... just far enough for a skilled player to collect all the rings and powerups and catch a breath from them.
 * This is the same case for the first Sonic Adventure game, but in its sequel, two-thirds of the cast dies upon falling into water (save the small patch in the Chao Gardens). This eventually became the case for everyone over the course of the 3D series while the 2D games retained the classic countdown.
 * The underwater Knuckles level "Aquatic Mine", which can be quite dangerous until you find the infinite oxygen item.
 * It is all rather selective, too - on some levels, Sonic displays exquisite Super Drowning Skills, dying if he so much as touches the rippling water at the very bottom of the game world (if you're lucky, he may only lose rings, and bounce back onto land). On others, water is a relatively benign substance, merely reducing your running speed and jump height (swimming is out of the question), and in some cases (where it takes up a significant portion or even all of the level) requiring you to find air to breathe. Worse, there are even some places where the two are mixed; go too deep on, say, the (Game Gear, Sonic 1) Jungle zone or the Aquatic boss fight, and you'll instantly pop your clogs. Maybe Hedgehogs are really sensitive to pressure?
 * While oxygen seems to be unlimited in the Monkey Island games, if Guybrush Threepwood stand around underwater for a really long time, he will die. This is really more of a gag death, as it's literally the only way to die in the games.
 * This is of course in reference to Guybrush's special talent to hold his breath for ten minutes (a fact he'll repeat to anybody willing to listen). You literally have 10 minutes to solve this puzzle/get out of the water, which is intentionally much longer than most people will need.
 * In Tales of Monkey Island, Guybrush can intentionally go underwater, and if you spend a little less than ten minutes of gameplay underwater, Guybrush will remember his limit and go back to dry land. Thankfully, there's only really one or two areas where you need to be underwater, they're incredibly straightforward to navigate, and like it's been said before, ten minutes is a generous amount of time.
 * The remake of Ninja Gaiden has one of this, but it ceases to be an issue once Ryu acquires an oxygen tank and draws on it from his Hyperspace Arsenal.
 * In Banjo-Kazooie, when the Oxygen Meter runs out, you immediately drown. Rusty Bucket Bay had oily water that not only drained the meter twice as fast when submerged, but drained it at the regular speed when on the surface. This is rectified slightly in Banjo-Tooie, where once the Oxygen Meter goes, your health starts to go down really quickly instead.
 * It's not really needed in Banjo-Tooie, either, seeing as the major underwater level gives you unlimited oxygen.
 * However, it does have another use in Banjo-Tooie: not only does it affect Banjo's ability to hold his breath under water, it also affects his ability to hold his breath in the presence of poisonous gas which Gruntilda uses against him in the final battle.
 * In Deus Ex, your health would also start decreasing when you run out of oxygen and start gulping water. While there are skills, items and Upgrade Artifacts to increase the amount of time you can hold your breath, the powerful health regeneration Upgrade Artifacts and instant-use medkits allow one to use Hit Points as an extra Oxygen Meter.
 * Bungie's Marathon series feature an especially heinous, literal Oxygen Meter: Your armored suit's HUD doesn't indicate how much oxygen remains in your lungs and blood, but in ITS compressed oxygen tanks! Since your suit lacks any way of refilling it with ambient oxygen, you must locate compressed oxygen dispenser panels or tanks of compressed oxygen to refill it. Worse yet, the player character apparently refuses to hold his breath, as if his suit's tank is empty he will instantly faint from even momentary immersion.
 * It's rare to have trouble with Oxygen underwater (or sewage, or lava), but the back-to-back vacuum levels (three in a row, if you visit a secret level) in Marathon Infinity have a nasty reputation. The one vacuum level in Marathon was also infamous.
 * Compare this with the Halo series' Master Chief/playable Elites, who can apparently stand around forever without anything to breathe.
 * World of Warcraft has two of these. A traditional oxygen bar for underwater, and a fatigue bar to prevent you from swimming out too far.
 * The first one can be bypassed by potions or spells. The second one on depleting completely begins draining your health, and can be circumvented by healing yourself to easily swim to the end of the map. The undead Forsaken can also stay underwater for much longer. This used to be significantly more useful until they extended the oxygen bar for all players, so that now everyone usually has plenty of time to fulfill their task.
 * They can't seem to decide on how long the oxygen meter should be, before the burning crusade expansion, and shortly into wrath, it was one minute long, halfway through wrath, they increased it to roughly five minutes, and as of cataclysm, it's back down to roughly two minutes.
 * Ecco the Dolphin. Justified of course, since the whole game was set underwater and dolphins can hold their breath for quite a while. When the oxygen meter runs out, health begins to drain.
 * In addition to being a certified death incarnate, Rico Rodriguez in Just Cause 2 can swim underwater for a ridiculously long amount of time. His oxygen is counted by a small circle that counts down from 99 by two every 2 seconds. This means that Rico can stay underwater for approximately one minute and 50 seconds. Yowza.
 * Tomb Raider uses a couple of variations on this; while most of the games use a standard oxygen meter, Tomb Raider: Chronicles used a special diving suit on one level that had confusing (since they never told you) additional mechanics: the suit had near infinite air, but as you bumped into walls and rocks Lara audibly becomes stressed and begins breathing heavily, at which point you begin to lose oxygen quickly, meaning you had to avoid hitting things. Tomb Raider 3 also has an underwater propulsion vehicle that makes you move faster, but it's argubly less useful than just swimming as it decreases your general mobility and must be got off of to use switches and other items. Water in arctic levels also had a hypothermia bar that went down faster than the oxygen bar, but functioned much the same way. In Legend and Anniversary, oddly, Lara is much slower underwater and has a much shorter air meter. Underworld changes things up again, with Lara going back to being almost as fast as in the original games, and having such a long oxygen bar it borders on Super Not Drowning Skills (that is in the rare instances where she swims without scuba gear, where it is that trope).
 * Decrease in health also functions differently depending on the game. Prior to Tomb Raider Legend, health usually decreases at a fixed steady rate. During and after Legend, the decrease in health rate is usually a slash of a quarter of the health bar every two seconds, or an eighth, depending on the difficulty level setting.
 * Super Smash Bros Brawl has an invisible one just for swimming. In the Subspace Emissary, some stickers can increase the length, but there really isn't any need for it.
 * Turok has a fairly unremarkable one, although you'd kind of expect a muscled-up warrior like him to be able to hold his breath a bit longer.
 * Cave Story has an oxygen meter which appears when the protagonist is underwater, although one might wonder why, since he's a robot. Players trying for the secret ending will eventually discover while saving Curly that surface robots are programmed to shut down if their systems get flooded with water, but this leads one to ask how carrying an oxygen tank enables one to survive underwater indefinitely.
 * Well, it is a bubble around the player, so the systems don't get flooded with water.
 * Swimming underwater in Gothic adds an oxygen meter in addition to the player's health and mana meters. When the Nameless Hero runs out of oxygen, the health starts draining instead, until he runs out of health and drowns. Notable because surfacing will make the meter invisible again, but will not instantly refill it--the player must stay on the surface for at least a few seconds, or will find on diving again that the meter isn't completely full.
 * The New Zealand Story did this, with the added implication that it may have actually been water in Tiki's lungs--swimming up to the surface would naturally allow your oxygen level to (slowly) replenish itself, but the process could be accelerated by spitting water. Pretty deadly water it was, too, as it could kill most enemies.
 * Conkers Bad Fur Day has one of these once you're able to swim underwater.
 * Radical Rex plays this entirely straight. Not only do you get a bar, but you have to either surface to refill it, or (ugh) lock lips with a big fat fish that is somehow able to maintain neutral buoyancy despite apparently being full of air. Oh, and if you touch the un-inflated fish (which this type will become upon giving up its payload), you'll lose a big chunk of air. There are also "bubble" powerups good for about half a deep breath. And if you get caught in the anemone's tentacles, the meter drains almost immediately to zero (though whether it's this or some kind of poison in them that kills you is debatable).
 * The Thief games have an oxygen meter that looks like a line of bubbles across the bottom of the screen. If you knock someone unconscious and dump him in water, he will die in about the same span of time you would (so don't dump unconscious guards in swimming pools if you're running a no-kill mission).
 * Averted in Thief: Deadly Shadows, where Garrett has learnt Super Drowning Skills
 * In Megaman Battle Network 5, there is a water dungeon which you have to guide your current Navi through. While they are underwater they are perfectly fine until they run out of "cyber-air" (really?), at which point their HP starts dropping rapidly until you either hit a cyber-air pocket or exit the water. Oh, and there's random encounters the whole way, including while you're attempting to fight the currents that push you back and drain your air, and while you're trying to avoid the whirlpools that drain your air. There's also three areas of this, each one progressively more frustrating. This is one instance Capcom cut something out of the English release for a good reason--in the Japanese version, there were four areas.
 * By the DS version, it was back up to four, which made for a rather annoying playthrough using a FAQ from Game FAQs, since one of the only really good ones was done by an editor ranting and raving throughout said FAQ about how they 'treated American gamers like babies' and went on and on about the Japanese version of the GBA release, instead of say, actual useful information about the game... Especially since, y'know, someone reading his walkthrough was likely to be playing the US version, or a version close enough that it didn't much matter.
 * When travelling on the ocean floor to Tane-Tane Island in Mother 3, the way you refuel your characters' collective oxygen bar is... interesting, to say the least. The amount of time you're able to survive without the aide of these machines is fairly realistic compared to most examples, though--around 30 seconds to a minute (with battles excluded).
 * You get them kissed by big-lipped mermen.
 * Non-underwater example: the Mr. Driller series has an Oxygen meter that slowly depletes as you play, with the oxygen loss accelerating once you make it deeper underground. To stay alive, you need to pick up air capsules scattered throughout the mine.
 * Jungle King / Jungle Hunt uses this during the swimming levels.
 * Alpha Prime uses an Oxygen Meter on the asteroid's surface, refillable through the use of oxygen dispensers, or simply by walking back into an airlock.
 * In Final Fantasy VII, the party has twenty minutes to defeat Emerald WEAPON, unless a party member is carrying the "Underwater" Materia, which replaces the timer with Super Not Drowning Skills.
 * In Dead Space, this becomes visible once you enter a vacuum. As it depletes, Isaac begins to choke and gasp, which is just wonderful for your concentration. Thankfully your time limit can be extended with upgrades to your RIG and restored with air canisters.
 * There's an optional underwater dungeon in Final Fantasy V that gives you a timer. The boss is a Puzzle Boss, just to make things more "fun". (It's Gogo the Mimic. How do you win? The faster you catch on, the more time you have to get out.)
 * Though really you need to get down there with long enough for the battle, and still have enough time to spare to either return to the submarine, or teleprot right back to it. It helps that there is a chest that wasn't in the area the first time you went there  that resets the timer.
 * Steel Battalion: Line of Contact adds one in the form of your view whitening up when the cockpit hatch is closed and your VT is shut down (either manually by toggle switches, the Rapier's Stun Rod, or the Earthshaker's Gauss emitter). Go without oxygen for too long and the pilot asphyxiates, taking you out of the match even if you have enough sortie points for another VT and deleting your pilot data.
 * In An Untitled Story, you even get upgrades that extend your oxygen meter.
 * Will Rock has the traditional meter for the underwater sequences. If it runs out, you can always replenish your health with healing packs and bandages if they're at hand.
 * A Variation, from Metro2033: Your wristwatch tells you how much time you have left on your gas mask before you need to switch filter canisters. Spend too long in areas with toxic atmosphere and you die. And you need to take off your gas mask as soon as it's safe to breathe, or it might get damaged the next time you get attacked in melee.
 * And since there's no HUD, you have to check your wristwatch constantly to see how much time you have before you have to change filters. And just because you're required to wear the gas mask doesn't mean it can't be damaged either, making any surface expedition a tense journey to avoid any serious conflict.
 * All three Disneys Magical Quest games have them, but the meter is only visible in the third.
 * In Jabless Adventure, your oxygen counts down from 100. It happens so quickly that you really can't accomplish anything underwater prior to receiving the SCUBA gear (which allows you to stay underwater indefinitely).
 * While you don't get a visible oxygen meter in Team Fortress 2, stay underwater long enough and your character will make drowning-type noises and take damage, eventually drowning. As with the Half-Life series above, health lost from drowning is restored by coming up for air.
 * Oddly enough, Medics and Dispensers can heal players faster than drowning can kill them.
 * Amusingly, some creatures in New Vegas will follow you underwater, despite having their own oxygen meter.
 * Doom 3 has the oxygen meter only visible outdoors. You can even refill it by getting scattered air canisters. Additionally you are rewarded with a loud breahting sound while moving outdoors.
 * Minecraft gives you small air bubbles underwater. Once used up you lose health and have a hard time moving around (or just up).
 * Kirby Mass Attack is one of the few games in the Kirby series which has that meter. This meter is shared by all the kirbies and the more kirbies the player has, the bigger the meter is.
 * The Rayman series plays with this a bit. The first game has Super Drowning Skills, the second has an Oxygen Meter which can be refilled by collecting blue lums, and the third let's you breathe underwater indefinitely.
 * Fisher-Diver has an oxygen meter. In addition to time, it also goes down when attacking the fish. This is one of the things to encourage using the harpoon sparingly.
 * Space Panic may have been the first game to have an oxygen meter, though it was really no more than a level timer labeled "oxygen."
 * Magical Doropie gave Doropie an oxygen meter in the underwater base levels. When it got low, it would beep until refilled by jumping into a convenient air pocket.
 * Terraria has an air meter that appears and depletes gradually when your character enters water (or lava, but if you're swimming around in that you generally have other problems). It allows you a decent amount of time, and if you're doing a long stint of underwater mining, you can always dig into a wall to create your own air pockets. Certain pieces of equipment like the Diving Helmet or the Breathing Reed make the meter deplete more slowly (the Breathing Reed also allows breathing if the end is still above the surface). The game also provides the Gills Potion, which makes you start drowning in air instead of water, and Neptune's Shell, which turns you into a Fish Person and allows you to swim and breathe.
 * Amusingly, if you attempt to equip a Fish Bowl as a helmet, you start drowning as if you were underwater. Which you kind of are, as far as breathing is concerned.
 * Endless Ocean essentially averts; it *does* have an oxygen meter for your air tanks, but it's a rather long one and most tasks get completed without running out of air ever being a factor. When it does run out, you get warped back to the boat. The sequel does tweak things a bit; dangerous fish attacking you knock your air out faster. Certain equipment upgrades up your air supply in both games.
 * Super Paper Mario uses a meter like this, but not for oxygen--the one place where Mario needs oxygen, he can somehow get all he ever needs from a goldfish bowl. No, the meter comes into play when shifting into 3D, where it depletes steadily and does damage if it runs out.