An item or event which increases the number of Video Game Lives the player will have to continue following death. Also known as extra lives, free men, or even life insurance.
In simpler games, where the player is a One Hitpoint Wonder, each time the player receives a critical injury or falls into an abyss, one life is deducted from his reservoir. When they are depleted, the game is over. More complex games deduct a life only when the Life Meter is emptied. Also, most modern games typically do something more friendly than simply end the game: the player is penalized, generally by having to restart the major area ("world", where losing a life with lives in reserve merely requires that the player restart the minor area), or from his last saved game. Some games used "continues", much like extra lives but senior to them.
The distinction between the stockpile of extra lives and the Life Meter has faded for most game genres.
Almost all games which measure lives include a means to increase the stockpile. Popular methods include:
A rare pickup item (or maybe common, if your game has Infinite 1-Ups). Often looks like a small version of the protagonist, or his face. It was even common once that the item's graphic would be no more than a literal rendering of the words "1 UP".
An exchange for some other game resource (especially game money).
In arcade games, inserting more coins.
The term is a shortening of the phrase "Player 1 Up", traditionally displayed in older arcade games where multiple players took turns playing, to let the first player know it was his turn. The notion dates clear back to pinball machines.
If this extra life is explained through in-universe technology, it is often an expendable clone, or a clOne-up.
Compare Auto Revive.
The DS game Drawn to Life has 1ups in the shape of your character's head. Which probably wouldn't be noteworthy, except that that means you determine what they look like; in this game, you're responsible for drawing your own player character.
Blood Omen has the Heart of Darkness, which, like previous examples, can instantly restore Kain to (un)life if he dies with at least one in his possession. They can also be used as healing items, and while they're available all over the place, there's a very sneaky (and awesome) way to instantly acquire 99 of them at once. And no, it's not a bug. Let's just say the Spirit Forges never specified that you had to sacrifice your blood...
In Ōkami, Amaterasu could come back to life with the help of her Astral Pouch, as long as it was filled with food.
There are also items called Golden Peaches which fully fill an Astral Pouch. Use it right after your Astral Pouch emptied to revive you, and you've got another life, basically.
In the SNES game, Legend of the Mystical Ninja, one late stage featured finding 1-up Icons sold in shops! Unfortunately, you had to make sure to buy the one for your character, or else you'd be spending your money on Player 2!
Fairly early in Indigo Prophecy, a character offers you a cross for protection. Accepting gives you an extra chance at quicktime events, and after the prompt (whether you accepted or declined) you'll start to find more crosses lying around on the ground in out-of-the-way places. Depending on the situation, the extra chance may mean shrugging off the failure (for instance, if you just got punched in the chest), or restarting the event (for instance, if you just got hit by a car.) Sadly, they provide no protection against failure from Sanity Meter loss, failure in the Stealth-Based Mission, or the occasional Non-Standard Game Over like taking aspirin with alcohol.
Rise of the Triad has two extra-life power-ups, which give 1 or 3 lives. There is a little catch, though: if your health is less than 75% when you pick one of these up, one of the lives from the power-up restores you full health instead of giving you an extra life. The game also include life items which will give you an extra life if you collect enough of them (they come in values of 1, 5, 10, and 25 and 100 are needed for an extra life). The game also gives you a bonus of 10000 points for every extra life you have when you finish the game.
In Descent and Descent II, 1UPs were in the form of extra ships, suspended in a green orb similar to shield orbs. You also got an extra life every 50,000 points, and when you finished the final level, each of your remaining lives added to your score.
Wolfenstein 3 D has them in the form of blue spheres with the protagonist's face on them.
Doom's Soul Spheres were originally extra lives, but changed to give you 100% health (beyond the 100% maximum, in a way acting as an extra life by doubling your survivability) when the concept of lives were removed from the game.
Serious Sam has extra life pickups in some of the games and some of the gamemodes of other games.
Time Crisis gives us perhaps the most difficult method of obtaining a 1-up in any Light Gun Game: you need to shoot 40 consecutive enemies without missing a shot.
In Resident Evil The Umbrella Chronicles and Resident Evil The Darkside Chronicles, the First Aid Spray that usually serves as a full health restore in the series acts more like an extra life, letting the players immediately continue a fight instead of being sent back to a checkpoint after dying. Notably, the instruction manual for the former game says the player can hold up to three of these items at once, but there's always exactly one per chapter and they don't carry over, so the limit never actually matters.
The traditional 1-up item in Super Mario Bros. and the Trope Maker is the green mushroom. Additional lives were also awarded for certain scores, or for collecting 100 coins. Before this usage, 1-up indicated it was the first player's turn in a multiplayer arcade game, such as Galaga.
Super Mario Bros. 2 kept the mushroom as a very rare item, but also allowed the player to win 1-ups in a slot machine based game between levels.
Super Mario Bros 3 had a sort of slot machine at the end of every level, where the player character would jump and strike the box to make it stop on one of the images inside — a fire flower, a star, or a mushroom. If you could hit the same symbol at the end of three levels in a row, you were rewarded with a number of 1-ups: 2 for three mushrooms, 3 for three fire flowers, and 5 for three stars. Even if the cards didn't all match, you'd still earn a 1-up for every three you collected*
But if you know what you're doing, it is quite easy to get stars every time if you jump at the box while the run gauge is maxed out, you'll get a star. The gauge must be maxed out when you first see "slot machine"
Super Mario World had, in addition to the traditional 1-up mushroom, the rare 3-up moon.
Its sequel, Yoshis Island, had 1-up clouds that were held by the feet of Fly Guys.
In Mega Man, the 1-up item was a Mega Man head. In later games, the item became a copy of Mega Man's helmet.
The Mega Man X series returned to the disembodied heads for the first three games, before the remainder of the series used helmets, while the Mega Man Zero and Mega Man ZX series both resorted to simple Z and ZX icons.
The classic platformer Monster Bash allowed the character to gain more lives by collecting voodoo-dolls of himself...
Super Mario Land and its sequel used the traditional heart shape as its 1-up. Because of the greyscale graphics, it wouldn't be possible to tell Super Mushrooms and 1-up Mushrooms apart, so in these two games the 1-ups are hearts. Super Mario Land 2 even has four different slot machines where you can get 1-ups, and the more expensive slots can give you multiple lives at once. At the most costly slot machine (requiring the maximum of 999 coins for one play), you can win a 20-up, a 50-up, or even a 99-up.
Conkers Bad Fur Day provides a handy explanation to the one-up system: upon dying for the first time, the player is taken to Death's door where Death explains that squirrels, much like cats, are exempt in death as they have as many lives as they "think they can get away with". From that point on, the player can collect squirrel tails around the game world to score extra chances. Whether this is a justification or a handwave is up to the reader's discretion.
In Donkey Kong Country you collect balloons with a picture of Donkey Kong's head (or Diddy or Dixie's heads in the first two sequels). When you die, one of your balloons pop, and when they're all gone, it's Game Over. There are also green 2-ups and blue 3-ups. There's even an enemy that takes 1-ups from you instead of killing you.
Sonic the Hedgehog: In all of the mainstream platformers you get a 1UP by destroying TV monitors with the character's head on it. Additionally, you can get a 1UP via Law of 100 with the rings you collect in the levels, though this noticeably harder compared to other series, due to Sonic losing rings when he takes damage.
Starting with Sonic 2, you also get lives for every 50,000 points you score in most installments.
One of the main reasons why Sonic Colors is the first Sonic game in ages you're likely to see the Game Over screen in more than once is that for the first time 100 rings don't give extra lives. The only way to get lives is to find them hidden in levels or get A rank or better or attack your score during the results screen.
In Sonic the Hedgehog 4 on consoles, you can match 3 cards with the Sonic symbol on it to get free lives in Casino Street Act 2. If you only get 1 or 2 cards at one time, they will stay on screen for 15 seconds or so. You can also match ring symbols (worth 10 rings for 3) or Eggman symbols (worth nothing).
The titular rabbit's head in the Jazz Jackrabbit PC game. A "One up!" sound effect plays when the item is collected. In the second game, the item was changed to a text item that said "1Up."
In Stinkoman 20 X 6, collecting an icon of Stinkoman's head grants the player an extra life. In an homage to this trope, the 20X6 version of Homestar is named 1-Up.
The first Rayman game had these in the form of figurines fashioned after the titular character. The Law of 100 also applied.
The first Banjo-Kazooie game had these in the form of golden statues in the shape of the bear.
In Spyro the Dragon, you would get a 1-up from purple chests that blinked. The 1-ups were mini-figurines of Spyro himself. In addition to that, if you defeated enemies that you have already killed for their gems, they will drop either the 1-up statues (very rarely), or the much more abundant silver orbs. Collecting 20 of these orbs gives you another life.
In Ripto's Rage and Year of the Dragon, the 1-up statues were replaced with blue butterflies. They could be found in either Glass Jars, or after killing every 10 fodder.
Paper Mario and its sequels have an item called a Life Shroom which automatically activates from inventory when Mario (or his partner, in Thousand-Year door) dies, keeping him alive and giving him 10 HP. They may also be selected from inventory.
The Mario & Luigi games have a 1-up Mushroom that restores the target player's health with half of his maximum HP. The 1-up Super does the same with full HP. In both cases, a character in the party must still be alive to administer it, and he uses his turn to do so.
While most RPGs have a checkpoint or "save-point" system for continuing, Fable also has Resurrection Phials, which are essentially OneUps which let you spring back to life (hence the name) on the exact spot where you bit the dust.
Brandish has the Ring of Life which similarly revives you right where you fell. Considering that you can find many health potions lying around, you can rest anywhere to quickly restore HP, and you can save at will, you might be able to go for a while without consuming the one you start the game with.
Likewise, Breath Of Fire III has the Soul Ring which saves the wearer from death with full HP, once. Through the Faerie Village Side Quest it is possible to get a near infinite amount of them, and you will likely need them to take on the bonus bossesin mook clothing, Berserker and Archmage.
Secret Of Evermore has an item called Pixie Dust and a call bead spell called Regenerate which will restore a small amount of HP if the Boy dies before they wear off.
Stargunner offers three ways of getting an extra life (none of them easy): collecting a rare extra life powerup in the game, buying them at the store between levels (they're quite expensive), or just getting enough points for a free one. The game awards free lives at 500000 points, 1 million points, and every million from then on. Mind you, it does take a lot to get a million points in the game and even the default top score (held by Duke Nukem) is 2 million points.
In the background, there are lights that correspond to different types of combos (i.e. shooting nothing but an entire column, shooting 10 enemies of the same color, etc). If you light all of these up, you get an extra life.
The roulette mini-game, comprised of spinning colored invaders, sometimes throws a yellow invader or two into the wheel of invaders. If you shoot the yellow invader, you get an extra life.
In the Every Extend series, you start with 12 lives, blow yourself up (and thereby lose a life) to attack, and gain extra lives very, very quickly. In fact, the term "extend" (a Japanese pseudo-anglicism used as a synonym for One Up) itself is in the title.
The Japanese survival horror game Fatal Frame has a particular item, the sacred mirror, that will replenish all of your health should you ever drop to zero hit points, in effect acting as a 1-Up. However you could only ever carry one of them at a time....
Similarly, the fairies (or magic medicines in the case of the Game Boy and DS games) in The Legend Of Zelda series will replenish your health when you run out, although in many cases it doesn't restore it all the way...
The Resuscitate item in Dino Crisis acts as a 1-Up; it revives Regina if she is killed, thus you can continue the game without having to reload your last save.
A one-up in the shape of Scott Pilgrim's head appears in Scott Pilgrim and the Infinite Sadness, just after he defeats his love interest's third "evil ex-boyfriend". It briefly creeps him out before he collects it.
Becomes a Chekhov's Gun when he finally uses it in the last volume.
A savvy Dungeon Master in Dungeons & Dragons can require a special rare spell reagent (or, in Fourth Edition, ritual component) for resurrection magic. Popular choices range from Phoenix Feathers or Anima Crystals all the way up to the tears of a dead god. The point is to maintain the game world's verisimilitude and give a reasonable explanation for why death is still treated as permanent and tragic by the majority of the people in the world despite the fact that resurrection magic exists. It also allows the players to loot "extra lives" from particularly difficult enemies (who are likely to have them in their treasure hoard as a form of life insurance anyway.) It's an elegant solution for keeping death from becoming cheap at high level without making it absolutely final.
In Homestuck, every player has a dreamself on either Prospit or Derse, which can be used as Extra Lives if the players get killed. There are a few exceptions - Sollux had two dreamselves due to his bifurcation gimmick, while Aradia didn't have one at all due to being a ghost. It later turned out that she did have a dreamself on Derse, it was just sleeping on a Quest Bed in a crypt instead of inside a tower like the rest. This turns out being very handy when Jack blows up Derse, allowing Aradia to ascend to the God Tiers. However, dreamselves have other uses aside from being spare lives, so oddly enough, the Extra Life is more valuable than the player's actual life. Having a dreamself alive in some way is necessary if a player is going to ascend to the God Tiers.
Minute To Win It, on those shows that it offered the "Blueprint Bonuses," had a 1-up as one of the two possibilities (the other was a 10-second bonus that you could apply to one attempt at one game).
A new British game show called Breakaway offers these as rewards for answering a Fame Game-style question correctly. (In the first season, the contestant that answered it correctly could choose to have their 1-up be at the expense of another player's lives, if anyone else had a life, but for the second season, that option was removed). Unlike most game shows that usethe conceptof lives, all lives are spare lives, which means that in and of itself, running out of lives does not eliminate you (in fact, nobody starts out with any lives at all). In the first season, the lives only come into play for players who have chosen to attempt a "Breakaway" (they're trying to claim all the money by finishing the stack on their own, or with only one partner), but now, on a wrong answer, anyone who had lives can choose to give up a life to avoid zeroing out the pot.
Fifteen To One gave any player who made it to the final round enough extra lives to give them a full set of three. It was slightly advantageous to have all three of your original lives in hand, though, since you started with one point per leftover life. (Slightly, because each question was worth 10, so the leftover lives from the earlier rounds were little more than a tiebreaker if two people survived to the end.)