Short for "'''killer application'''", a '''killer app''' is a game - or something not a game that's a category killer - so good that it's considered a must-own if you have the system it's released for, and is in fact a reason in and of itself to buy said system.

When you buy {{literature}}, you get a single self-contained experience: the book contains all there is to this particular adventure. When you buy a ticket for a {{film}} or a [[{{Theatre}} stage show]], you get two hours of drama, and that's all there is to see (until the inevitable sequel, that is). But electronic hardware isn't like that. Music players, movie players, computers, video game consoles, tablet computers... They all require ''software'' to run, and each piece of software delivers a different experience: a photo-editing suite can't be used to balance your checkbook, for instance, or vice versa. As such, hardware and software are separate yet interlinked categories, and one is used to judge the other: the same piece of software might run much more efficiently on one computer than another, and you'd factor that in when deciding what hardware ''or'' software to buy. And, just to add to the confusion, a fair amount of software is ''exclusive to one piece of hardware'', or family of hardware: for instance, Microsoft for the longest time resisted releasing its "Office" suite of productivity software (Word, Excel, [=PowerPoint=], etc) for [=iPad=], to keep their competing "Surface" tablets relevant.

And that's where we get to this trope. A "killer app" is a piece of software that validates the hardware. It provides such an excellent user experience that it justifies buying the hardware.

The term is primarily used within the world of video gaming, but originated outside it: it was used, especially during the '90s Internet boom, to describe the mythical invention that everyone in America needed and which would make its developers -- and their investors -- rich beyond their wildest dreams.

The term can also be used on a more serious context, used to refer to a very useful application which immediately becomes a "must-have", which is, in fact, the original meaning if the term. It's first been applied in 1979, when a first spreadsheet application, [=VisiCalc=], was released for UsefulNotes/AppleII, and became a must-have virtually immediately, spawning hordes of clones and imitations on numerous platforms.

And, indeed, when the term is applied in this manner, only a very few applications apply, including word processors, spreadsheets, database management programs, email clients, and web browsers. The only thing everyone agrees on is that any new hardware attempting to launch itself should have a Killer App at hand, especially if the hardware itself is a video game console--that business is more software-driven than any other.

While most products that attain killer app status are extremely successful and popular, it should be noted here that "creating a true killer app" is akin to "writing the Great American Novel": everybody ''wants'' to, but nobody has yet created (or is likely to create) the definitive killer app.

Note that a killer app is more than just a good game. A game can be good, great, critically acclaimed, even an all-time classic... and still not be this (conversely, not all killer apps are great by modern standards; some of them seem quite dated today). A killer app is insanely popular in its own time, enough so as to single-handedly drive sales for its system. The examples that follow, then, are not just the games that tropers loved, but rather the games that ''everyone'' loved; the ones that made their respective systems.

Arguing over which killer app provides the most bang for its buck is a large part of the UsefulNotes/ConsoleWars. If an anticipated game shares the same genre as an existing Killer App, it may be called a [Insert Game Here] Killer, however this often puts [[ToughActToFollow unrealistic expectations]] on the upcoming title.

Compare StarMakingRole (equivalent for actors) and BreakthroughHit (equivalent for creators).

%% And don't list killer apps that "might be". Wait until the results, even if they get listed as "failed to be one".

* ''VideoGame/SpaceInvaders'' was a major system mover for the UsefulNotes/{{Atari 2600}}, quadrupling its sales, making it the UrExample.
* Atari was counting on both ''VideoGame/PacMan'' and ''Film/ETTheExtraTerrestrial'' to be killer apps for the 2600, and had each produced in wildly optimistic numbers; in fact, more ''Pac-Man'' cartridges were produced than there were Atari consoles, on the assumption that the game would be so popular people would buy consoles just to play it. As it turned out, they were only half-right, as [[IncrediblyLamePun they did help to kill the Atari 2600]], [[UsefulNotes/TheGreatVideoGameCrashOf1983 and very nearly the entire industry]].
* ''VideoGame/StarRaiders'' was a bona fide killer app for the UsefulNotes/Atari8BitComputers; many people bought the computer just to play the game.
* ''VideoGame/AlienVsPredator'' and ''VideoGame/{{Tempest}} 2000'' were this for the otherwise ill-fated [[UsefulNotes/AtariJaguar Jaguar]].
* On the computer side of Atari, the presence of MIDI ports was what made the UsefulNotes/AtariST the go-to machine for electronic musicians.

* Coleco's competitive acquisition of the console license for Creator/{{Nintendo}}'s ''VideoGame/DonkeyKong'' is the main reason the UsefulNotes/ColecoVision console was a contender in the second generation UsefulNotes/ConsoleWars. It is rumored that the company released an intentionally poorly-designed version of the game for the Atari 2600, just to make their own system look even better by comparison.

In general, Nintendo has about a dozen {{Cash Cow Franchise}}s that can reliably be counted on to move systems when new titles come out, the most notable being ''Franchise/SuperMarioBros'', ''Franchise/{{Pokemon}}'', ''VideoGame/MarioKart'', ''Franchise/TheLegendOfZelda'', and ''VideoGame/SuperSmashBros''. The first two franchises also happen to be the best-selling video game series in the world.
* UsefulNotes/NintendoEntertainmentSystem:
** ''VideoGame/SuperMarioBros1'' is often credited with saving the North American video game industry following the UsefulNotes/TheGreatVideoGameCrashOf1983. ''VideoGame/SuperMarioBros2'' and ''VideoGame/SuperMarioBros3'' followed suit a few years later, and this trilogy secured the Top 3 list of best-selling games for the system.
** When the NES first launched it came with R.O.B., your VideoGame/RoboticOperatingBuddy. R.O.B. could play only two games, both of them considered mediocre at best, and the R.O.B. itself only seemed to function half the time.[[note]]And when R.O.B. did function, it moved so slowly that you were better off doing R.O.B.'s controller inputs yourself.[[/note]] However, it was key in making the system seem less like a "videogame console" (which was a dirty word at the time, considering the video game crash of the early 80s). Essentially, it was a ''fake'' Killer App: something that seemed like the must-own technology of the future that handily snuck the far more important hardware into homes.
* UsefulNotes/GameBoy:
** ''VideoGame/{{Tetris}}'' was released as a pack-in game for the system, and would go on to be the most popular PuzzleGame of all-time.
** ''VideoGame/PokemonRedAndBlue'' debuted late in the system's lifespan, single-handedly revitalizing sales of the handheld.
* UsefulNotes/SuperNintendoEntertainmentSystem:
** ''VideoGame/SuperMarioWorld'', was packaged with all SNES units. It would later become the most [[GameMod modded]] game of all time as that community began to grow.
** ''VideoGame/SuperMarioAllStars'', a updated compilation of the NES Mario games[[note]](including the first international release of ''VideoGame/SuperMarioBrosTheLostLevels'', the Japanese ''Super Mario Bros. 2'')[[/note]] also proved the viability of the UpdatedRerelease concept.
** The SNES also floated high on ''VideoGame/TheLegendOfZeldaALinkToThePast'' and the port of ''VideoGame/StreetFighterII'', which was packaged with the console in some countries.
** The ''VideoGame/DonkeyKongCountry'' series allowed the SNES to remain popularity and relevance into the 32-bit era, while Creator/{{Sega}} stumbled with the [[UsefulNotes/OtherSegaSystems Sega CD, 32X]] and UsefulNotes/SegaSaturn confusion.
* UsefulNotes/VirtualBoy:
** The sysem didn't really have much going for it, but those who have played ''VideoGame/VirtualBoyWarioLand'' agree that it was the one game truly worth playing on the console.
* UsefulNotes/{{Nintendo 64}}:
** ''VideoGame/SuperMario64'' was one of only two launch titles for the system and stands one of the first 3D games circumvent the PolygonCeiling that other 2D franchises struggled with at the time. The game remains as one of the most influential in its genre and is the most popular game played in the {{speedrun}}ning community.
** The first entry in the ''VideoGame/SuperSmashBros'' series was both this and a SleeperHit, with the title's success surprising many executives within the company.
** As time went on, between the output of Nintendo's internal development teams and Creator/{{Rare}}, the system gained other landmark titles such as ''VideoGame/MarioKart64'', ''VideoGame/GoldenEye1997''[[note]](often credited alongside ''VideoGame/Halo1'' as the game to popularize the FirstPersonShooter on consoles)[[/note]], ''VideoGame/TheLegendOfZeldaOcarinaOfTime'', and ''VideoGame/DonkeyKong64''.
* UsefulNotes/GameBoyAdvance:
** Multiple ''Pokémon'' games catalyzed the GBA sales at a very high rate. The best-selling titles on the Game Boy Advance were ''VideoGame/PokemonRubyAndSapphire'', which sold over 15 million units, ''[=FireRed/LeafGreen=]'', which sold over 10 million units, and ''Emerald'', with over 6 million units. Even the ''VideoGame/PokemonMysteryDungeonRescueTeam'', a spinoff by a 3rd party which also was sold on the DS as Blue version, was one of the system's top 20 selling titles, beating out games like ''VideoGame/KingdomHeartsChainOfMemories'', ''VideoGame/GoldenSun'', ''VideoGame/MetroidFusion'', and ''VideoGame/TheLegendOfZeldaTheMinishCap''.
** {{Updated Rerelease}}s of NES and SNES games, such as the ''[[VideoGame/SuperMarioBros2 Super]] [[VideoGame/SuperMarioWorld Mario]] [[VideoGame/SuperMarioWorld2YoshisIsland Advance]]'' [[VideoGame/SuperMarioBros3 titles]] and ''The Legend of Zelda: A Link to the Past'' appealed both to those who never played the originals and those that liked the idea of playing these games on-the-go.
* UsefulNotes/NintendoGameCube:
** ''VideoGame/SuperSmashBros Melee'' is '''the''' UsefulNotes/GameCube killer app, being one of the most anticipated games for the system when initially announced. Considered by some to still be the best installment of the franchise, it's still being played [[TournamentPlay competitively]] more than 15 years after its release: a shockingly long life for a FightingGame that is surpassed only by ''VideoGame/MarvelVsCapcom2'', which was released just one year earlier.
** ''VideoGame/MetroidPrime'', a FirstPersonShooter take on a then-dormant ActionAdventure/[[PlatformGame Platformer]] franchise surprised many ''Franchise/{{Metroid}}'' fans with its high-quality[[note]]Creator/RetroStudios was an unknown American developer that had only a string of cancelled projects to its name[[/note]] and mature feel[[note]]Nintendo had developed a "kiddy" stigma compared to more teen/young adult-focus given off by Creator/{{Sony}}'s UsefulNotes/PlayStation2 and newcomer Creator/MicrosoftStudios' UsefulNotes/{{Xbox}}[[/note]]. The game went on to sell 2.8 million copies, making it the 7th best-selling game on the system and the best-selling entry in the franchise to-date. The "[[ Top 10 GameCube Games]]" video from Website/ScrewAttack sums it up well:
-->''When [[VideoGame/MetroidPrime this game]] was first announced, [[TaintedByThePreview we thought it was going to]] '''suck'''. [[AndYouThoughtItWouldFail How wrong we were. How wrong we were.]]''
** ''Resident Evil 4'' was intended to be this, as it was released as part of the "Creator/{{Capcom}} 5: an deal to bring five new, exclusive games to the [=GameCube=] to support the platform. Unfortunately, one of them (''Dead Phoenix'') was [[{{Vaporware}} never released]], three of them (''Resident Evil 4'', ''VideoGame/ViewtifulJoe'', ''VideoGame/{{Killer7}}'') were eventually ported to the UsefulNotes/PlayStation2, and the only game to remain a [=GameCube=] exclusive (''VideoGame/PN03'') didn't sell many copies and was critically panned.
** At the console's release, ''Franchise/StarWars: VideoGame/RogueSquadron 2'' was considered the system's Killer App at launch and even held this title after ''Smash Bros. Melee'' was released a couple months later. When the console was released in Europe, ''Rogue Squadron 2'' was its top selling game, beating out Nintendo's first party titles.
* UsefulNotes/NintendoDS:
** The system's surprise success was pushed by more casual games such as ''VideoGame/{{Nintendogs}}'' and ''VideoGame/BrainAge'' just as much as it was by new entries in established Killer App franchises (''VideoGame/NewSuperMarioBros'', ''VideoGame/MarioKart DS'', and [[VideoGame/PokemonDiamondAndPearl two]] [[VideoGame/PokemonBlackAndWhite generations]] of "Pokémon"). ''Pokémon Black and White'' became the fastest-selling games for the platform as well, despite coming out towards the end of the system's life.
** ''VideoGame/AnimalCrossing: Wild World'' was an even more popular sequel to the [=GameCube=] installment, and remains the best-selling game in the franchise (beating out ''New Leaf'' by less than a million).
** The remake of ''VideoGame/FinalFantasyIII'' wasn't a system killer app, but denoted the start of major third-party support for a gaming system the rest of the industry was skeptical of.
** UsefulNotes/DSiWare had ''VideoGame/PhotoDojo'', a fighting game where you could take pictures/sound recordings to create fighters, including yourself. Also, you could make your own stages this way.
* UsefulNotes/{{Wii}}:
** Similar to the Nintendo DS, much of the Wii's success is the result of more causal games. The "Wii" franchise of games (started by the pack-in launch title ''VideoGame/WiiSports'') is the 5th best-selling video game franchise of all-time at 201.8 million copies sold between the various ''[[VideoGame/WiiSportsResort Sports]]'', ''[[VideoGame/WiiPlay Play]]'', ''[[VideoGame/WiiFit Fit]]''.
** ''VideoGame/SuperMarioGalaxy'' is the best-selling 3D PlatformGame of all-time. ''VideoGame/NewSuperMarioBrosWii'' became the third best-selling platformer ever, beaten only by other entries in the ''Super Mario'' series, and is seen by some as the start of the genre's resurgence on consoles. Similarly, ''VideoGame/MarioKartWii'' and ''Super Smash Bros. Brawl'' became the best selling games in the history of their genres.
* UsefulNotes/Nintendo3DS:
** ''VideoGame/TheLegendOfZeldaOcarinaOfTime 3D'' served as this for the system, which was struggling to gain traction. Within two weeks of its Japanese release, [[ it had sold over 600,000 copies]], or over 20% of the install base. It raised 3DS sales by over 50% the week it came out as well, despite not being released in the West until the following week.
** The ''VideoGame/MonsterHunter'' franchise serves as this, though mostly for Japan, each entry selling at well over 2.5 million its home country alone. ''Generations'' is the best-selling installment, at over 4 million units.
** ''VideoGame/SuperMario3DLand'' sold over five million copies in just two months worldwide, outselling games like ''VideoGame/GearsOfWar 3'' and ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'' on the UsefulNotes/Xbox360. ''Mario Kart 7'' sold 4.3 million in 5 weeks. Put together, the two Mario games represent a third of 3DS software sold in 2011. Combine those Mario games with ''Ocarina of Time'' and ''VideoGame/{{Nintendogs}} + cats'', you have over one half of all 3DS software sold through 2011.
** ''VideoGame/AnimalCrossing: New Leaf'' sold two million copies in Japan alone in less than six weeks, and has gone on to sell almost as much as ''City Folk'' on the Nintendo DS. This success and the game's nature as a [[SimulationGame life sim]] also did much to push Nintendo's attempts at publishing major titles digitally through the [=eShop=].
** ''VideoGame/PokemonXAndY'' ended up selling four ''million'' copies in its first two days of sales and became the fastest-selling 3DS game of all time...until ''VideoGame/PokemonSunAndMoon'' released a few years later and completely broke those records[[note]]in part thanks to VideoGame/PokemonGo returning the franchise to levels of popularity unseen since the late 1990s[[/note]] to quickly become the second best-selling game on the system, less than a million copies behind ''X and Y''. Meanwhile, ''[[Videogame/PokemonRubyAndSapphire Pokémon Omega Ruby and Alpha Sapphire]]'' sold 3 million copies in its first three days.
** ''Super Smash Bros. for 3DS'' sold a million copies in its opening weekend in Japan alone.
** ''VideoGame/FireEmblemAwakening'', despite selling much less than the previously-mentioned games, was the best-selling game of the franchise (by a wide margin) until [[VideoGame/FireEmblemFates its sequel]] was released three years later. It's also notable in that was not only successful enough to increase the franchise's popularity in the West, but also prevent the series' cancellation, as declining sales meant ''Awakening'' was intended as the final game.
* UsefulNotes/WiiU
** ''VideoGame/NewSuperMarioBrosU'' launched with the Wii U and is the second best-selling game on the system, but the release of ''VideoGame/NewSuperMarioBros2'' is considered to have diminished its impact. In that respect, the following year's ''VideoGame/SuperMario3DWorld'' is considered the first real system-seller.
** Nintendo pushed ''VideoGame/MarioKart8'' as this, to an almost aggressive extent. In addition to releasing a premium Wii U bundle in many regions [[note]]The North American bundle included the game, a complete Wii U Deluxe system, a Mario-themed Wii Remote Plus and Wii Wheel; Europe got a similar bundle plus two special Mario and Luigi-themed bundles that included some additional goodies such as a strategy guide[[/note]], they also had a program where ''every'' copy that had been purchased in the two months after the game's release --including those that came in the bundle-- could be registered on Club Nintendo[[note]](their consumer loyalty program at the time)[[/note]] and redeemed for one ''free Wii U game of your choice''. North America had 4 options to choose from[[note]]''VideoGame/NewSuperMarioBros U'', ''Wii Party U'', ''VideoGame/TheLegendOfZeldaTheWindWaker HD'', and ''VideoGame/{{Pikmin}} 3''[[/note]], while Europe and Australia got 10[[note]]The four aforementioned games plus ''VideoGame/TheWonderful101'', ''VideoGame/MonsterHunter 3 Ultimate'', ''VideoGame/SonicLostWorld'', ''[[VideoGame/WarioWare Game and Wario]]'', ''VideoGame/NintendoLand'', and ''[[VideoGame/MarioAndSonicAtTheOlympicGames Mario and Sonic at the Sochi 2014 Olympic Winter Games]]''[[/note]]. As a result, ''Mario Kart 8'' sold 1.2 million copies in its first weekend alone and boosted the console's sales in every region. Wii U sales in Europe, for example, rose by ''666 percent''. The game would go on to be the best-selling game on the system, with '''a 3:5 attach rate'''.
** ''VideoGame/SuperSmashBros for Wii U'' managed to sell 490,000 physical and digital copies sold during its first three days of availability alone, despite the availability and success of a 3DS version which was released two months prior.
** There's also ''VideoGame/EarthBound'' being released for the Wii U's UsefulNotes/VirtualConsole, which became one of the top downloaded titles for the service. Not bad for a game that was an AcclaimedFlop when it first came out. ''VideoGame/EarthBoundBeginnings'' was also received with similar praise, and quickly raised to the top of the downloads charts. Not bad for a game that [[NoExportForYou wasn't released outside Japan]] before then.
** ''VideoGame/{{Splatoon}}'' became a SleeperHit, selling over one million copies worldwide in less than a month and eventually becoming the best-selling Wii U game in Japan despite the shooter genre [[AmericansHateTingle not being all that popular in the region]].
** ''VideoGame/SuperMarioMaker'' sold 1 million copies in its first two weeks of availability, thanks to months of hype and promotion.
%%* The worldwide supply problems with Toys/{{amiibo}} due to demand being much higher than expected would make that figurine line Nintendo's Killer App for its merchandise and peripherals front.
* UsefulNotes/NintendoSwitch:
** ''VideoGame/TheLegendOfZeldaBreathOfTheWild'', despite also seeing release on the Wii U. Nintendo reported at the end of the launch month that they'd sold more copies of ''Zelda'' for Switch than they did ''actual Switches'' -- there were significant amount of people who had bought ''Breath of the Wild'' for a Switch they ''didn't yet own''. By the end of the 2017 Zelda managed to sell over six million.
** ''VideoGame/Splatoon2'' sold 671,000 physical units during its Japanese release weekend alone, outselling ''literally every other game on the Switch in that region in the process''.[[note]]For reference, Zelda and Mario Kart 8 Deluxe had sold 543k and 588k respectively over the course of ''months''.[[/note]] In one month, it sold over a million copies in Japan alone.
** ''VideoGame/SuperMarioOdyssey'' received universal acclaim and managed to sell ''two million'' copies within its first three days, immediately reaching more than a quarter of the install base for the Switch. Within two months, it even managed to overtake ''Breath of the Wild'' in sales, reaching heights of ''nine'' million.

* The ''Franchise/SonicTheHedgehog'' series on the Mega Drive[=/=]UsefulNotes/SegaGenesis, as well as the first ''VideoGame/MaddenNFL'' game for (U.S.) sports fans. The bloody version of [[VideoGame/MortalKombat the first]] ''Franchise/MortalKombat'' also was a boon in distinguishing it from the SNES.
* The Genesis port of the arcade version of ''VideoGame/{{Strider}}'' was also one of the system's earlier killer apps. In addition, the game holds the distinction of being the first game to be released on an 8-megabit cartridge.
* ''VideoGame/MichaelJacksonsMoonwalker'' gave the Genesis a big push, thanks to the novelty of being able to play as [[Music/MichaelJackson the King of Pop, himself]].
* [[VideoGame/AladdinVirginGames The Genesis version]] of ''Disney/{{Aladdin}}'', made by Virgin Games in partnership with actual Disney animators, was the 3rd best selling game for the system, and this version did not come to the SNES, due to Creator/{{Capcom}} still holding the rights to make Disney games on Nintendo systems at the time.
* When ''VideoGame/LunarTheSilverStar'' was released in Japan, it sold almost as many copies as the [[UsefulNotes/SegaGenesis Sega CD]]. That, and ''VideoGame/SonicTheHedgehogCD'', were, if not killer apps, the nearest thing the Sega CD/Mega CD had.
* Sega's ''VideoGame/VirtuaFighter'':
** The first game was such a huge hit in arcades that its various ports sold more than half of all 32X and UsefulNotes/SegaSaturn machines in Japan.
** ''Virtua Fighter 2'' was the killer app for Saturn.
** ''VideoGame/SakuraWars'' was the other Saturn killer app in Japan. The first and second games recorded the biggest sales as a Saturn original title, and was ranked #13 place in the Famitsu's 100 all-time favorite games list, leading the series to become one of Sega's most successful franchises.
* The ''VideoGame/PanzerDragoon'' series are killer apps for the Saturn, despite the fact that the first was the only one that sold well.
* ''VideoGame/NightsIntoDreams'' served as a primary reason to buy a Sega Saturn. Other games for the system with massive popularity include ''VideoGame/VirtuaFighter'' and ''[[VideoGame/{{Bomberman}} Saturn Bomberman]]'' (often referred to by reviewers as the best game in its series).
* The beyond-the-arcade port of ''VideoGame/SoulCalibur'' was ''the'' reason to get a [[UsefulNotes/SegaDreamcast Dreamcast]], even though it wasn't enough to move sales of the system. Interestingly, the death of the Dreamcast (and the end of Sega's hardware history) was heralded by EA denying Sega a port of ''VideoGame/MaddenNFL'', the same killer app that made their own company what it is today, and wouldn't have done so without the parent company's help. EtTuBrute
** However, ''[=NFL2K=]'' was one of the rare sports killer apps, becoming one of the biggest sellers at launch along with ''another'' killer app in ''VideoGame/SonicAdventure'' (the final true Sonic killer app), and garnering enough rave reviews that it instigated a still-strong backlash against ''Madden NFL'' once EA won the bid to become the sole manufacturer of NFL games. Although Sega was able to fill the void with that and its equally-well-received ''NBA 2K'' counterpart, no EA support did punch a big hole in the DC's third-party support.
** ''VideoGame/{{Shenmue}}'' had generated considerable hype for the console, and is widely considered the best game on it, but its huge budget eventually led to it becoming a financial failure despite solid sales.

* When the UsefulNotes/TurboGrafx16's CD add-on came out, NEC's marketing division, TTI, was quick to promote the two CD ShootEmUp titles available for it, ''Gate of Thunder'' and ''Lords of Thunder'', as being its flagship titles, even ahead of console mascot Bonk. ''VideoGame/{{Ys}} Books 1 & 2'' was also highly lauded. In Japan, the first big game produced for the CD-ROM unit was ''VideoGame/TengaiMakyou: Ziria'', but neither it nor its more popular sequel was ever exported.
* Similarly locked to Japan was the [=SuperGrafx=], which boasted arcade-perfect ports of ''[[VideoGame/GhostsNGoblins Ghouls 'n Ghosts]]'' and ''VideoGame/{{Strider}}''.

* ''VideoGame/BattleArenaToshinden'' was hyped as the first killer app for UsefulNotes/PlayStation, a "''VideoGame/VirtuaFighter'' Killer". It took at first, but the quality of later games overtook it and now it's currently forgotten and considered to not have aged well at all. The first true killer app ended up being {{Creator/Capcom}}'s ''VideoGame/ResidentEvil'', with ''Franchise/TombRaider'', ''VideoGame/MetalGearSolid'', and especially ''VideoGame/FinalFantasyVII'' following up to make the [=PlayStation=] a viable contender against Sega and Nintendo. And to a lesser extent, the ''Franchise/CrashBandicoot'', ''Franchise/SpyroTheDragon'', and ''VideoGame/SyphonFilter'' series. The system's sheer number of killer apps is the main reason it was able to take the video game throne from Nintendo in the mid '90s.
** Creator/SquareSoft's decision to develop ''VideoGame/FinalFantasyVII'' for the [=PlayStation=] over the N64 played a huge role in Sony's victory over Nintendo during the 32/64-bit era.
* The UsefulNotes/{{PlayStation 2}} received five major killer apps in 2001: ''[[VideoGame/GranTurismo Gran Turismo 3: A-Spec]]'', ''VideoGame/AceCombat04ShatteredSkies'', ''VideoGame/FinalFantasyX'', and especially ''VideoGame/MetalGearSolid2SonsOfLiberty'', plus ''VideoGame/GrandTheftAutoIII''. Coincidentally -- or perhaps not -- this coincided with release of two of its competitors' consoles, the [=GameCube=] and Xbox.
** Due to the anticipation generated by its pre-release hype, ''Metal Gear Solid 2'' is credited for the [=PlayStation=] 2's victory over the Dreamcast before the game was even released. The game then went on to being one of the top 10 best-sellers, with over 7 million copies sold.
** The ''VideoGame/GrandTheftAuto'' series of games had been killer apps for the [=PlayStation=] from ''GTAIII'' onwards[[note]]Rockstar did release Xbox and PC versions, but they came later[[/note]] until Microsoft pulled a major coup and convinced Rockstar to make ''VideoGame/GrandTheftAutoIV'' a multi-platform release on day one.
** ''VideoGame/MetalGearSolid3SnakeEater'' is widely considered one of the [=PS2=]'s best games (if not the best), and also one of the system's top 10 to top 15 best-sellers.
** Also of note is the ''Franchise/RatchetAndClank'' series, which was so successful, Ratchet ended up becoming the new face of Sony after Crash and Spyro went third-party.
** The [=PS2=] had so many killer apps lined up that ''VideoGame/GodOfWar'' doesn't make this list simply because it just flat-out wasn't needed.
** ''VideoGame/ShadowOfTheColossus'' is another game that can fit the category, with its ability to push the capabilities of the [=PS2=] far enough for the sake of SceneryPorn.
* The ''VideoGame/GranTurismo'' series were killer apps on the [=PS1=] and [=PS2=], but Sony Computer Entertainment's fumbling of the ''[=GT5=]'' release may have prevented this status for the [=PS3=]. But that's not the case for ''[=GT6=]'', which not only received a lot of support from car companies(Vision GT is an example), but also got a great reception from the fans for being a huge upgrade from ''[=GT5=]''.
* ''VideoGame/MonsterHunter'' is widely credited with keeping the PSP afloat in Japan, particularly ''Freedom Unite / Portable 2nd G'' and ''Portable 3rd''. Another was ''VideoGame/CrisisCoreFinalFantasyVII.''
* ''VideoGame/MetalGearSolid4GunsOfThePatriots'' was the biggest killer app for the [=PS3=], and what ended most of the hate for the system. What's most notable is that Snake's [[GuestFighter appearance]] in ''VideoGame/SuperSmashBros Brawl'', specifically his own stage, has a massive amount of {{Foreshadowing}} for this game. ''[[{{Irony}} Foreshadowing on the killer app of a direct competitor]]''.
** ''VideoGame/GodOfWar III'', though not hurt by being released at the time the price cut was taking effect.
** The ''VideoGame/{{Uncharted}}'' series has been this, but it has never been more apparent than with ''VideoGame/Uncharted3DrakesDeception'', which sold [[ 3.8 million copies during the first day of release]], something rarely heard of for console exclusive games.
** ''VideoGame/{{Killzone}} 2'', which is essentially the ''Halo 3'' for the [=PS3=].
** ''VideoGame/TheLastOfUs'' [[ has sold 6 million]] in less than a year, making it the 2nd best-selling exclusive behind ''Gran Turismo 5'', and 3rd best-selling [=PS3=] game overall. It is almost unanimously seen as ''the'' defining game of the [=PS3=], if not the entire seventh generation. Its UpdatedReRelease on [=PS4=] is this too, for those who didn't play it on [=PS3=] but bought a [=PS4=].
* ''VideoGame/GravityRush'' became this for the UsefulNotes/PlayStationVita as it was offered for free for Playstation Plus members for the better part of two years since its launch release.
** ''VideoGame/{{Tearaway}}'' is this too (despite not being released on the PS Plus line-up). It also uses [[TechDemoGame most, if not all the console's features]] in many, creative ways.
** ''VideoGame/{{Persona 4}}: [[UpdatedRerelease The Golden]]'' is this for the Vita in Japan, which was lagging behind. It sold 137 thousand copies along with 34 thousand units. This later proved true for the Western market as well.
** IGN once posed the question of whether or not VideoGame/SoulSacrifice was the Vita's killer app despite Sony never claiming it to be.
** The Vita ports of the ''Franchise/DanganRonpa'' series in the West, due to the PSP versions being a case of NoExportForYou.
* ''VideoGame/{{Bloodborne}}'' is this for the UsefulNotes/{{Playstation 4}}. After 16 months since the console released, this is the first non-Nintendo game from the Eighth Generation to be acclaimed by both critics and players. ''VideoGame/{{Driveclub}}'' is this to a lesser degree in the UK, becoming the best-selling exclusive of 2014. However, the game was bundled on a relatively cheap Black Friday bundle.

* The ''Franchise/{{Halo}}'' franchise cemented the Xbox as "the {{FPS}} console", leading to the FPS "arms race" between Microsoft and Sony that lasted through TheNoughties. ''VideoGame/HaloCombatEvolved'', a launch title for the Xbox, single-handedly saved Microsoft from being a mere footnote in the Console Wars. ''VideoGame/{{Halo 2}}'' went on to become a KillerApp for the UsefulNotes/XboxLive multiplayer service, and ''VideoGame/{{Halo 3}}'' then became one for the UsefulNotes/Xbox360.
* The game that proved the Xbox could do something ''other'' than FPS was ''Videogame/KnightsOfTheOldRepublic'', which spurred sales off the console close to ''Halo'' levels.
* Upon the Xbox 360's release, the most purchased title was ''Videogame/CallOfDuty2'' (with a port from the PC version, in contrast to the watered-down ones the previous generation got). Then in the next two years there was ''VideoGame/GearsOfWar'' and ''VideoGame/{{BioShock|1}}'' (the latter, like ''Call of Duty'', also available on PC upon release).
* Like the UsefulNotes/GameBoyAdvance, UsefulNotes/XboxLiveArcade has sold mainly on a stream of solid indie, ranging from ''VideoGame/GeometryWars'' to ''VideoGame/SplosionMan''.
* This trope is mostly inverted when it comes to Japan, as they have not taken to either system much like its competition. So far, the closest the 360 has to a killer app there is a hit game that boosts sales for a week or so then they fall back to just selling a few thousand a week until the next hit game. These "boost" games include ''VideoGame/BlueDragon'' (Creator/AkiraToriyama's involvement helped, too), ''VideoGame/AceCombat6FiresOfLiberation'', ''VideoGame/TalesOfVesperia'' (which is the best-selling 360 game in Japan and was even sold with [=360s=] for a while, so it was a {{Fanboy}} issue when it was later ported to the [=PS3=]) and ''VideoGame/StarOceanTheLastHope''.
** For Xbox Live in Japan, the Killer App is ''VideoGame/TheIdolmaster'', even if it isn't for the 360 itself. On the release of the Xbox 360 version, Microsoft sold over four times as many Microsoft points as they had in the past. THE iDOLM@STER singlehandedly resparked the sales for the Xbox 360 in Japan. The success was so great that in some stores they had to close the doors ''early in the morning'' because they were sold out.
* The ''VideoGame/{{Forza}}'' games, with its two series ''Forza Motorsport'' and ''Forza Horizon'', are Microsoft's racing killer app, designed to target the [=PlayStation=]'s ''VideoGame/GranTurismo'' series. ''Forza'' has sold millions, and the [[LoadsAndLoadsOfCharacters wide variety of cars]], [[DesignItYourselfEquipment customization]], [[{{Itasha}} painting]], and (in ''Horizon''[='=]s case) the amazing [[WideOpenSandbox open worlds]] and [[AwesomeMusic/{{Forza}} music]] makes it '''the''' go-to racing simulator for the Xbox.
* ''VideoGame/{{Titanfall}}'' was the game that kept the UsefulNotes/XboxOne from dying on the vine in its first year, being a desired "exclusive" for the console[[note]]in the sense that it didn't come out for [=PS4=], at least[[/note]] 'til ''VideoGame/Halo5Guardians'' was released. Oddly, it ''wasn't'' a blockbuster, just a game that kept interest alive in the then-controversial system. Electronic Arts, however, in a move that [[SarcasmMode just so happened]] to soften developers Respawn Interactive for acquisition, treated it like it ''was'' a killer app and foolishly had ''VideoGame/Titanfall2'' compete with ''VideoGame/{{Call of Duty|InfiniteWarfare}}'' and ''VideoGame/{{Battlefield|1}}'', resulting in poor sales, despite being available for the UsefulNotes/PlayStation4 as well as the Xbox One and PC.

* The original classic Mac's killer app was its four channel sampled audio, a feature [[ItWillNeverCatchOn very nearly nixed by Steve Jobs]]. The feature went on to become the Mac's selling point in the US as the feature meant that the Mac could have "talkie" games that were technically unheard of in the era. The demonstration of [=MacinTalk=] during its launch was one of the major selling points. This, combined with the fact that early '90s Macs were the also the first computers to ship with CD-ROM drives as standard equipment, cemented its status as an edutainment machine in schools and as the all-rounded family multimedia machine in homes in the '90s. Of course, it helped that VideoGame/{{Myst}} was one of the killer apps for the platform, appearing for the Mac first before being ported to Windows [[note]]Myst was originally written in [=HyperCard=], a Mac-specific programming language[[/note]].
* '''''Videogame/{{Doom}}.''''' The biggest Killer App in all of PC gaming history, with over 4 million copies sold. Before ''Doom'', PC games were a niche hobby, a small subset that was to console[[note]]or, to put it in more periodic terms, "Atari/Nintendo/Sega"[[/note]] players what video games were to the general populace. ''Doom'' made PC gaming mainstream, and let the world know that those computers they were using for their essays and spread sheets could do something that not just matched, but even ''surpassed'' what those boxes next to their [=TVs=] could do. To call it the ''Franchise/SuperMarioBros'' of PC gaming is an understatement; it singlehandedly ''made the PC the new Nintendo'', and only after its success can you watch a movie or TV show and see anybody playing video games on their computers as opposed to sitting by the television playing on a console. Even to ''this very day'' it's the first (and often only) title that comes to non-gamers' minds when they think of PC games, with ''VideoGame/CallOfDuty'' only recently supplanting this honor.
** ''Doom'' was indirectly the TropeMaker for Windows as a serious gaming platform. Prior to Windows 95, you were limited to ''Solitaire'' and ''Minesweeper'' and the occasional more advanced title like ''Myst''. And then Bill Gates read the result of a study that found that ''Doom'' was installed on more computers in the world than Windows was. Intent on remedying this, Bill made damn sure that Windows 95 would have its own natively compatible version of ''Doom''.
* The final straw that made Windows into a viable gaming platform, and the only place to play games on PC, was [=DirectX=]. Prior to [=DirectX=], developers often had to roll their own graphics code, and if they wanted to support graphics accelerator cards, they usually had to make a different version of their game for each brand of card. [=DirectX=] remedied this by giving developers an UsefulNotes/ApplicationProgrammingInterface of pre-built graphics functions that could run on any third-party graphics card that supported it (which was most if not all of them). Given that it was exclusive to Windows, it also had the side effect of largely killing off or decimating the gaming scene (to the extent that it still existed) on other computer platforms.
* Windows 3.0 as a whole for mice on the PC market. Before Windows 3.0, most PC users only had a keyboard, and mice were deemed to be "for DTP pros". Coincidentally, point-and-click adventure games from Creator/{{Sierra}} and Creator/LucasArts also started appearing around that time, which bolstered mice sales even more.
* The most important game on PC in terms of actually ''selling hardware'' was ''Links 486''. This game actually forced owners to upgrade from 386 to 486 processors '''''just to play it'''''. VideoGame/{{Quake|I}} in turn spurned many a gamer to update to Pentiums.
* Try thinking of a PC game before ''VideoGame/KingsQuest''. Outside of the ''VideoGame/{{Zork}}'' series of {{Text Adventure}}s, it's not a very easy task. The colorful, imaginative adventures that Creator/{{Sierra}} brought to life gave gamers something appealing that console games, with their straightforward running and jumping and shooting, just couldn't offer: an interactive, immersive world you could get lost in as it unfolded in vivid graphics, text details and cutscenes. [[SeinfeldIsUnfunny Even if they aren't exactly vivid by today's (or even the latter half of the decade's) standards]], it was enough to convince a lot of people why you would want to play video games on the "homework machine".
* Creator/{{Bungie}} seems to make killer apps wherever they go. [[UsefulNotes/AppleMacintosh Mac's]] killer app? The ''VideoGame/{{Marathon}}'' Trilogy. The Xbox's? ''{{Franchise/Halo}}''.
* The ''VideoGame/{{Ultima}}'' franchise was the crown RPG of early [=PCs=]. So much so, it had a profound effect on NES [=RPGs=] for a long, long while. Like other series, it forced some users to upgrade their hardware to play ''Videogame/UltimaVII''.
* In the same vein as ''Doom'', ''VideoGame/HalfLife'' and its sequels pushed the success of PC games even further, with their slick design and fantastic presentation bridging the gap between "casual" gamers raised on mascot platformers and Japanese [=RPGs=] and "hardcore" gaming formats. It was, after all, the computer equivalent to ''VideoGame/GoldenEye1997'' in shifting the FPS scene from "Doom clones" to [[FromClonesToGenre an actual genre]].
** ''VideoGame/CounterStrike'' was, ironically, both the killer app for the early 2000's golden age of 'real world' LAN Gaming cafes/centres, as well as the reason they crashed in popularity from 2004 onwards, when the Source remake became the killer app for UsefulNotes/{{Steam}} and home-based online multiplayer.
** Valve did it again with ''VideoGame/TeamFortress2'' in 2007, which is, to this very day, their most successful game ''of all time'', and tied with ''VideoGame/{{DOTA 2}}'' (also by Valve) as the most popular game on Steam until VideoGame/PlayerUnknownsBattlegrounds overtook it in 2017.
* ''Franchise/StarWars: VideoGame/RebelAssault'' was THE killer app for CD-ROM, although some say that the time of CD-ROM had dawned and ''Rebel Assault'' was just the first major game.
* There are two candidates for the cross-platform killer app for CD-ROM drives: ''VideoGame/TheSeventhGuest'' and ''VideoGame/{{Myst}}'', both often bundled with the drives people bought in order to play them. Interestingly, unlike many of the other games on the list, they currently have a bit of a SeinfeldIsUnfunny status.
* Attempts had been made for ages to sell 3D accelerators, and while 3dfx's Voodoo made a good argument, it was a combination of ''[=GL=]VideoGame/{{Quake|I}}'' and ''VideoGame/{{Unreal|I}}'' that caused people to pour hundreds of dollars into enough system upgrades to see them rendered through Glide.
* ''VideoGame/{{Crysis}}'' was a boon for graphics card manufacturers, as even ''years'' after its release, hardcore computer gamers have been working hard to build systems that can render its incredible graphics at full detail. It was also important because at the time, other developers who weren't abandoning the PC altogether were [[PortingDisaster making ports that were vastly inferior]] to their own contemporary UsefulNotes/Xbox360 or UsefulNotes/PlayStation3 versions for no good reason - not taking advantage of the more powerful hardware available to [=PCs=] (sometimes not even acknowledging that [=PCs=] could ''have'' different hardware by letting you change the graphical settings), making little effort to properly port the controls from a controller to keyboard and mouse, ignoring existing bugs and often introducing new ones that would also go ignored, et cetera. Some say that this game single-handedly saved the platform and jump-started its renaissance.
* Since [[UsefulNotes/AppleMacintosh Macs]] have historically had few compatible games, every gamer who owns one is essentially required to get certain games. Some examples are the ''VideoGame/{{Marathon}}'' Trilogy, and anything made by Creator/BlizzardEntertainment. Preemptively, Valve releasing Steam and the Source-based games on Mac (''VideoGame/{{Portal 2}}'' and ''VideoGame/Left4Dead2'' in particular) have caused a huge jump of interest in Mac gaming. The same thing has happened to UsefulNotes/{{Linux}} since the announcement that Valve would be porting Steam to Ubuntu.
* ''VideoGame/TheSims'' can be credited with kicking off the resurgence of casual gaming of the 2000s (along with internet games).
* The ''VideoGame/AgeOfEmpires'' series, ''VideoGame/AgeOfEmpiresII'' in particular, was one of the most successful and well crafted PC RTS games of its time, and still maintains a large player and modding community despite being a decade old.
* The LAMP server (Linux, Apache, MySQL, and PHP) let people build servers using off-the-shelf PC hardware, giving Linux a huge boost in its early days. Along with powering much of the Internet, it quickly became the standard for individually-owned game servers.
* Windows XP only really started to die off in favour of Windows 7 when ''VideoGame/{{Battlefield 3}}'' was announced to be Windows 7/Vista exclusive. ''VideoGame/CallOfDutyBlackOps2'' making the same announcement a year later likely helped as well.
* 64-bit versions of Windows were slowly gaining speed by the start of TheNewTens, and multiple games coming out from a few years into the decade have been requiring 64-bit [=OSes=] to even run, but it's most likely the PC port of ''VideoGame/GrandTheftAutoV'' that's been the biggest cause for people to upgrade.
* Creator/TelltaleGames singlehandedly resurrected the AdventureGame genre.
* While VideoGame/NetHack is a multi-platform game, just about any serious Unix or Linux user has a copy installed, as it's one of the few decent games available.
* Looking for decent games on the Windows 8 store? Look no further than Creator/{{Gameloft}}'s games (except the ''{{VideoGame/My Little Pony|Gameloft}}'' game--[[PortingDisaster that's a different story]]), which even have their own collection easily visible on the front page of the store.
* Because Chromebooks are available on dirt-cheap hardware, are centrally managed and there's no real software to manage, they've become popular in schools.

* The original ''VideoGame/SamuraiShodown'' on the UsefulNotes/NeoGeo home console.
* ''VideoGame/MetalSlug'', especially ''3''.

[[folder:Other Systems]]
* ''B-17 Bomber'' for the UsefulNotes/{{Intellivision}}.
* [=NewTek=]'s ''Video Toaster'' was the one selling point of the UsefulNotes/CommodoreAmiga that made said machine popular at video production houses and film studios. The ability to genlock (or synchronize video timing signals) made it easy to overlay text on video, thus making the Amiga the go-to machine for {{Fan Sub}}s. ''Deluxe Paint'' was another program that sold Amigas.
* VideoGame/TowerFall was the closest thing the Kickstarted ''Ouya'' console had to a killer app before ''[[UpdatedRerelease Towerfall: Ascension]]'' came to [=PS4=] and PC.
* The UsefulNotes/BBCMicro was guaranteed good sales in the education and office market thanks to being [[BackedByThePentagon Backed By The Government]].[[note]]when Creator/TheBBC's educational programming department first got serious about computer science, every manufacturer had their own fork of BASIC that was almost but not ''quite'' compatible with everyone else's, so eventually they realised the only way to have a set of programming exercises that'd work for everyone was to commission a computer designed to their own specifications. Acorn Computers won the contract and the rest is history.[[/note]] But without sales of ''VideoGame/{{Elite}}'', it's unlikely they'd have made much if any headway in the home computer market, much less become as iconic in British geek culture as they are.
* ''VideoGame/{{Touhou}}'' for Western interest in the UsefulNotes/PC98.
* ''VideoGame/DefenderOfTheCrown'' for the UsefulNotes/{{Amiga}}.

* Creator/PopcapGames owns the casual genre. Most casual games are tweaked knockoffs of Popcap's efforts, which in turn are just variations of match-3, spot-the-difference, time-management and various simple luck/skill-based physics minigames. Doesn't matter. Popcap owns the entire genre. There are still entire blocks of people who would never call themselves 'gamers' who are obsessed with ''VideoGame/{{Bejeweled}}''.
* ''VideoGame/TeamFortressClassic'' was, for the longest time, THE online shooter. ''VideoGame/CounterStrike'' took over, and for the longest time the market was since fragmented between [=WW2=] and modern or futuristic shooters.
* ''VideoGame/GuitarHero'' turned {{Rhythm Game}}s from [[{{Creator/Konami}} weird J-Pop things]] (in the eyes of many) to a major western phenomenon.
* Though it had less casual-appeal than the above, ''VideoGame/DanceDanceRevolution'' kept the arcade scene afloat single-handedly, and no doubt was an inspiration for the physicality of gaming aspects that would become part of the Wii's appeal. Years later, ''Just Dance'' would turn dancing games into a genre in its own right, and incidentally helped Ubisoft become the Wii's biggest supporter outside of Nintendo.
* Do you like RealTimeStrategy games? Then you ''must'' have tried two of Creator/BlizzardEntertainment's best games: ''VideoGame/{{Starcraft}}'' and ''VideoGame/WarCraft III''. Or the ''VideoGame/CommandAndConquer'' series. In the following years, the ''VideoGame/DawnOfWar'' series or ''VideoGame/CompanyOfHeroes'' also count.
* Similarly, do you like [[TurnBasedStrategy turn-based]] FourX? If so, then at least one of the ''VideoGame/{{Civilization}}'' games is probably in your library.
* For {{MMORPG}}s, ''VideoGame/WorldOfWarcraft''. It's the one everyone's heard of, and it has slightly more players than the next 2 biggest (''VideoGame/GuildWars'' and ''Knight Online'') ''put together''. And for browser [=MMORPGs=], it's ''VideoGame/{{Runescape}}''.
* Do you like Japanese [=RPGs=]? You probably have a ''Franchise/{{Pokemon}}'', ''Franchise/FinalFantasy'', or ''VideoGame/DragonQuest'' game. In fact, ''VideoGame/DragonQuest'' is such a killer app in Japan that even [[SalaryMan Salarymen]] will take a day off and students from the most prodigious schools will cut class just to buy a copy on the day it becomes available for sale.
* While still relatively obscure overseas (except for the ''[[CashCowFranchise Persona]]'' series,) ''Franchise/ShinMegamiTensei'' is right up there with Japanese role-playing games in Japan.
* Do you like Western [=RPGs=]? You've probably played ''Franchise/TheElderScrolls'', series or ''VideoGame/BaldursGate''. Alternately, if you like Western [=RPGs=] but high fantasy's not your thing, you've probably got at least one ''VideoGame/{{Fallout}}'' or ''Franchise/MassEffect'' game in your library.
* ProfessionalWrestling has really only had one game that could be considered a killer app - ''VideoGame/WWFNoMercy'' for the N64. ''No Mercy'' had a big roster, an in-depth storyline mode, a very detailed for the time create-a-wrestler function, many different types of matches, and good multiplayer. Even people who don't like professional wrestling often like ''No Mercy'', and the game still has an active modding community today. The next closest example would probably have to be ''WWE Smackdown: Here Comes The Pain''.
* Fancy yourself a fan of fighting games? Then you must have played a ''Franchise/StreetFighter'' game. In fact, ''VideoGame/StreetFighterII'' introduced many fighting game mechanics that persist to this day.


* ''VideoGame/{{Myst}}'' was '''the''' killer app that transformed the CD-ROM drive from a mildly interesting computer curiosity into an absolute must-have feature.
** ''Myst'' '''was''' a killer app for the Mac, as was originally written for the Mac and appeared around the time CD-ROM drives first started becoming standard equipment on Macs.
** When the game was eventually ported to the PC, it also made sound cards a must in every PC. One '''must''' have a sound card to fully enjoy the game, and after the title, any PC that doesn't have a sound card is considered a poor man's PC. Prior to that, sound cards were largely considered a luxury peripheral that is unnecessary for mainstream gaming. It also helps that all sound cards made back then has a built-in proprietary CD-ROM port, which is needed if you're going to add a CD-ROM drive to the PC because all CD drives manufactured at that time only either supported the SCSI interface (mainly because Macs, UsefulNotes/{{Amiga}}s and UsefulNotes/{{Atari ST}}s back then used SCSI for the hard disk and CD-ROM drive, and thus SCSI came as standard on them) or a non-IDE proprietary interface.
* ''Film/TheMatrix'' is widely acknowledged to be the killer app for the DVD format. Every store front had the hallway assault and the rooftop bullet time sequence playing on the screens and so many people bought their first DVD player with a copy of ''The Matrix'' that the movie might as well have been bundled with the player. It was the first DVD million-seller.
** Also a two-in-one of sorts: The [=PlayStation=] 2 benefited greatly from having a built-in DVD player. In some regions it was in fact the cheapest DVD player on the market for several months.
** A lot of people also bought DVD players just to use Creator/{{Netflix}}.
** [[BetterOnDVD The ability to blow through entire seasons of TV shows]] in a weekend was also a major selling point for [=DVDs=].
* The UsefulNotes/BluRay format had a similar Killer App: ''Film/{{Avatar}}'' sold 1.5 million copies on its ''first day'', 6.2 million after three weeks. It's also not surprising that the [=PlayStation=] 3 was the most popular Blu-ray player.
** An earlier Killer App for the format was ''Series/PlanetEarth'', one of the first nature documentaries entirely shot in HD and one of the first television series to take advantage of the new format. Unsurprisingly with all the SceneryPorn it contained it quickly became a chart-topper back in the early days of the format.
* Let's not mince words: [[TheRuleOfFirstAdopters Pornography has been a killer app for EVERY new form of communication]], from the printing press to the camera to the UsefulNotes/{{VCR}} to {{the internet|IsForPorn}}. An oft-repeated [[ (and fairly shaky)]] urban legend claims that Creator/{{Sony}}'s refusal to license porn films on their proprietary Betamax format was the deciding factor in Betamax losing to VHS in the videocassette format wars of the '80s; it was actually VHS' longer recording time and substantially lower price that helped it beat Betamax despite inferior video and sound quality, and the porn studios likely went with VHS because that's what all their customers were using. Still, the legend was persistent enough that Sony decided not to make the same mistake again with Blu-Ray.
* ''WesternAnimation/TheSimpsons'', ''WesternAnimation/FamilyGuy'', and ''Series/{{Firefly}}'' proved that DVD series box sets were both financially lucrative and did not ruin reruns of regular TV. See also: {{Uncancelled}}.
** The case was proved long before ''Firefly'' came along. ''Series/BabylonFive'', for example, made half a billion dollars for Warner Bros several years earlier.
* ''VideoGame/HalfLife2'' and ''[[VideoGame/CounterStrike Counter-Strike: Source]]'' were responsible for UsefulNotes/{{Steam}}'s success today, and the popularity of digital distribution as a whole, though that might have something to do with the games ''[[UsefulNotes/DigitalRightsManagement requiring]]'' Steam to play.
* What ''Film/TheMatrix'' was to [=DVDs=], {{Music/Dire Straits}}' album ''Music/BrothersInArms'' was to [=CDs=], as it was the first album to sell over a million copies in the format and the first to outsell the LP version. The albums's insanely high sound quality showed off what those shiny little discs could do.
** {{Music/Pink Floyd}}'s ''Music/TheDarkSideOfTheMoon'' was also a killer app for [=CDs=], as the album's high sound quality had long been used to demonstrate audio equipment. At one point in TheEighties EMI had an entire CD plant dedicated to churning out copies of ''Dark Side of the Moon'', and this was when there were only ''two'' CD pressing plants in the entire world!
* Music/TheBeatles' ''Rubber Soul'', ''Revolver'', and ''Sgt. Pepper's Lonely Hearts Club Band'', as well as Music/TheBeachBoys' ''Pet Sounds'', have been cited as killer apps for albums for pop[=/=]rock music.
* ''VideoGame/AngryBirds'' lives on as one of the most popular games for many formats, but ''especially'' for [=iOS=] devices.
* Creator/{{Netflix}} is the killer app for a lot of streaming set-top boxes, including Apple TV and Roku, as well as many game consoles with those capabilities. For many people, the only reason to get a Netflix account was to see their original programming. One show of theirs in particular has become a true killer app: ''Series/OrangeIsTheNewBlack.'' A couple of years later, ''Series/{{Daredevil 2015}}'' came in to fill the action niche and a year later, ''Series/StrangerThings'' has done this for science fiction.
* The resurgence of vinyl's mainstream popularity was spearheaded by Music/{{Beck}}'s ''Guero'' (2005) and Music/RedHotChiliPeppers' ''Stadium Arcadium'' (2006), both of which were explicitly mastered much better on vinyl than they were on digital formats. Many bought turntables just to play them.
* Although cassette tapes had been selling steadily since their introduction in the '60s, with playback improvements helping them overtake 8-track sales in the '70s, it was with the introduction of the Sony Walkman in 1979 that the cassette format really took off. The ability for people to take their own music with them was irresistible. Prerecorded cassettes finally overtook [=LPs=] in sales in the middle of the '80s before the CD boom around the turn of the decade.

* For Creator/CartoonNetwork, ''What A Cartoon!/World Premiere Toons'' and later ''Creator/CartoonCartoonFridays'' both proved to be this, as it was a launching pad for the network's original series. And within the network itself, Creator/{{Toonami}} is credited with ushering in the mainstream Japanophilia boom of the early-to-mid 2000s, primarily for introducing the anime phenomenon to the West with shows like ''Manga/SailorMoon'' and ''Anime/DragonBallZ''.
* If one goes even earlier, you can credit ''Anime/{{Voltron}}'' for anime's expansion in the USA and abroad. Its most notable and innovative (at the time of course) feature was the Stereophonic Soundtrack that ''Anime/GoLion'', its original version, lacked. This feature made it THE show to air to showcase the Stereo capabilities of most affiliate stations and systems.
* For the UsefulNotes/AppleII, the killer app wasn't a game at all (though there were an awful lot of those): it was the first electronic spreadsheet, [=VisiCalc=]. And for the IBM PC, it was the spreadsheet program Lotus 1-2-3. Because 1-2-3 was written in assembler and used specific hardware tricks to run faster, it was a de facto test of clone compatibility.
** Spreadsheets seem to get a lot of this: Excel, for example, is Microsoft Office's Killer App. It also helped two [=WIMP=][[labelnote:*]]Windows/Icon/Menu/Pointing Device[[/labelnote]] platforms get off the ground: first, it was one of the killer apps for Macintosh, and a couple of years later (1987) Excel became the main reason to use the fledgling Microsoft Windows. Spreadsheet programs attract the killer app label because the complex financial and statistical functions they enable are exponentially more difficult--sometimes functionally impossible--without the visual/computational assistance of the spreadsheet. Think about how headache- and eyestrain-inducing a complex spreadsheet is (unless you're into that sort of thing). Then imagine ALL the same information presented in a hard-copy ledger. Killer. App.
** [=VisiCalc=] alone was selling ''more'' Apple ][ than all of its games combined, actually, and its need for a screen real estate and RAM was a real driver for the Language Card (which added more memory) and 80-column Card ([[ExactlyWhatItSaysOnTheTin self-evident]]), and a real reason why both these upgrades were later officially incorporated into the motherboard design. IBM took notice, and they made sure that there was a port for the UsefulNotes/IBMPersonalComputer when it launched two years after [=VisiCalc=] in 1981. Apple would eventually have its own killer app for the //e (and its [=ProDOS=] operating system) with [=AppleWorks=], one of the first integrated software packages (combining a spreadsheet, word processor, and database). Apple didn't even advertise it heavily at first, because they didn't want to step on the toes of their third-party vendors (nor overshadow their own [=AppleWriter=]), but it still sold so well that it even outsold Lotus 1-2-3 for a while. Its later-generation versions, however (sold by Apple-spinoff Claris, spun off to dodge accusations of antitrust violation under the product name [[CaptainObvious [=ClarisWorks=]]], on both Mac '''and''' PC, were eclipsed by Microsoft Office and by Corel's iconic word-processing product [=WordPerfect=].
* Almost all of the killer apps for UsefulNotes/MacOS X are made by Apple. Half of them come with the system.
** Apple originally made a number of killer apps directly on the original Macintosh's launch -- [=MacPaint=], [=MacDraw=], and [=MacWrite=] -- that have been the gold standard ever since for WIMP GUI image editors, drawing programs and word processors. But it was the first WYSIWYG page layout program, [=PageMaker=], that made desktop publishing possible and guaranteed the Mac's most lucrative niche. [=PageMaker=] was also a killer app for UsefulNotes/MicrosoftWindows when it was ported over, before Windows became really popular.
** Apple's OS is the killer app of the UsefulNotes/{{Macintosh}}, and recently, [[ Parallels]] is a very good killer app for Intel Macs since it makes the "you can't play as many games on a Mac" argument obsolete.
* In America, ''Series/ILoveLucy'', ''Texaco Star Theater'', the Army-[[RedScare McCarthy]] hearings, and the 1960 Presidential debates were television's Killer Apps. In Britain, the coronation of Queen Elizabeth II was this.
** JFK's assassination was also a killer app. Everyone watched the news, and forget about work happening the next day.
** The moon landings were this in, of all places, UsefulNotes/SouthAfrica. When the people of South Africa realized that they were the only people in the Western world who couldn't watch Neil Armstrong take his one small, historic step on the surface of the moon, they pressured their government to end its ban on television programming (which it viewed as [[NewMediaAreEvil a morally corrupting influence]]). They finally lifted the ban in 1975.
** Ironically, for Japan, which was still only barely out of the post-war devastation and overwhelmingly poor (it was worse there than in North Korea, actually) it was ''also'' the Elizabeth II coronation. People were taking out five-year loans with ridiculously rip-off rates just to be able to watch it.
* In Britain, the killer app for colour [=TV=] was snooker. The 1969 BBC show ''Pot Black'', which showed a single frame of snooker each week, was made to increase the sales of colour [=TV=] sets. Although it was really more of a [[TechDemoGame Demo App]] showing what could be done with colour TV that wasn't possible with black and white. People didn't rush out to buy colour TV sets just to watch the snooker - it took until 1977 for the number of households with colour TV to exceed those with black and white.
** The series produced the all-time infamous quote from commentator Ted Lowe: "And for those of you who are watching in black and white, the pink is by the cushion next to the green".
** In America, ''Series/{{Star Trek|TheOriginalSeries}}'' was the killer app for color TV. This was an interesting sort of chicken-or-the-egg case where one helped the other and vice versa, with color TV more or less being the reason why the original ''Star Trek'' stayed on the air as long as it did. While NBC had wanted to cancel it, their parent company RCA wanted to keep it for two reasons: they owned the patent for color TV, and ''Star Trek'' was the primary reason Americans bought them. RCA made more money selling color [=TVs=] to ''Star Trek'' fans than NBC lost by not giving its time slot to something else.
** In Brazil, it was TheWorldCup in 1974 that led many to purchase color TVs.
* The 1990 Gulf War was [[GallowsHumor proverbially]] the killer app for 24-hour cable news, specifically Creator/{{CNN}}. Where national networks had to eventually return to their regularly scheduled programming after Iraqi phone lines were cut off, CNN had previously had a permanent line installed and continued broadcasting round-the-clock.
** Three years earlier, the "[[ Baby Jessica In The Well]]" story was another KillerApp for CNN, and possibly the TropeMaker for the whole "24-hour breaking news" concept.
* The addition of GPS has been a huge mover for handheld computers. Presumably the medium as a whole is based around the want for calendar and contact programs.
* Taxi work seems to be the Killer App for hybrid cars. No fuel is consumed idling in dense city traffic or waiting for fares, the battery packs are barely affected by massive mileage and indeed seem to thrive on constantly being in use compared to being parked 22-plus hours a day like most personal cars, and both the financial and environmental cost/benefit ratios increase compared to private use.
** The same thing served that purpose for diesel cars from the 50s to the early 80s. While private customers were turned away by their bad performance and work culture, those things did not matter too much in taxi work, while the high mileage that cabs get made the benefits of diesels' better reliability and lower fuel consumption more sizeable.
** The fuel efficiency of Japanese cars is what caused them to take off in the U.S. during the oil crisis of the 1970s. It's no accident that the Toyota Prius became popular during the high gas prices of the '00s as well.
* The Internet had been around in a form similar to what we use today since at least the early 1980s, but it was NCSA Mosaic, the first easy to use web browser available for [=PCs=] and Macs, that made the network a must-have for computers.
* Bittorrent is the killer app for consumer internet download speed, download caps, and hard drive capacity. Website/YouTube was also a killer app for broadband.
* Creator/{{MTV}} was the killer app for cable TV. For sports fans, the killer app was Creator/{{ESPN}}.
* {{UsefulNotes/UNIX}}'s killer app, as with UsefulNotes/MacOS, was originally the platform itself, with the ability to redirect input and output at the shell. Another killer app was Website/{{Usenet}}, a precursor to modern social media. The real killer app for Unix was the C programming language. While C itself is portable, a lot of C developers tended to assume a Unix environment. Even on non-Unix systems, compiler makers try to emulate as much of a Unix environment as possible, inluding tools like make. Fortunately, it was relatively easy to port Unix to new hardware. Software development is the biggest non-server use for Unix and Linux systems.
* Website/{{Twitter}}, Website/{{Facebook}} and other social media services are the killer apps for smartphones and tablets.
** Blackberry messenger was a killer app for Blackberry phones, unfortunately for them that changed once cross platform messaging apps appeared in Android and iOS.
* Literature/TheBible was the killer app for the printing press, and with it mass literacy, compulsory education in the Western world, and the Protestant Reformation.
* Guns were part of the reason for the development of interchangeable parts and mass producing.
** If one wants to get a little dark, UsefulNotes/WorldWarII was the killer app for the above as they were applied to firearms, especially after the logistics nightmare that was caused by the lack of these among the Allies' standard Chauchat machine guns back in UsefulNotes/WorldWarI. It's part of the reason the famous Thompson SMG was retired essentially immediately after the war ended - other SMG designs that came about in the midst of the war did its job just as well but could be produced much faster and at half its cost.
* Travel. There are some places every tourist will go when traveling to specific cities or countries. Examples include the Eiffel Tower for France and the Statue of Liberty in New York.
** In the past, pilgrimages provided a killer app to make the risks and expense of travel worthwhile -- plus saving your immortal soul! Pious people would make pilgrimages to holy springs, sites of martyrdom, even all the way to the Holy Land -- so in a way, TheBible inspired a Killer App for travel in medieval Europe.
** And, of course, Muslims took pilgrimages to Mecca (and Medina and Jerusalem) before it was cool.
* Some people have suggested invoking killer app when it comes to buying new electronics, namely by testing the hardware by using something that would prove its quality. Specifically, in one article about buying a new television, the reporter suggested taking a DVD of ''Film/MoulinRouge'' to the electronics store with you, saying that if a TV could stand up to its fast pace and bright color palette, it can handle almost anything.
* ''WesternAnimation/SouthPark'' was this to Network/ComedyCentral. When it was picked up, channel viewership was mediocre among cable networks, and there were still cable providers who didn't provide it in their basic package. It created a boom of overall channel viewership and a demand for Comedy Central. ''Series/TheDailyShow'' and ''Series/TheColbertReport'' are also credited with building and keeping audience, but not quite in the same numbers or rate as ''South Park''.
** To a lesser extent, ''Series/ChappellesShow''; considered one of Comedy Central's best programs and popular enough to still be aired years after it ended ([[ShortLivedBigImpact and despite its short run]]). Much like South Park, it also has its fair share of [[FollowTheLeader imitators]].
* Getting the UsefulNotes/{{NFL}}'s NFC coverage from Creator/{{CBS}} (as well stealing some of their staff) turned Creator/{{Fox}} from a group of stations that aired ''WesternAnimation/TheSimpsons'' and ''Series/MarriedWithChildren'' into something that its ancestor Creator/DuMont couldn't: the Fourth Network of American Television.
* The ''Manga/AttackOnTitan'' anime was one for Crunchyroll.
* Unquestionably, Creator/{{HBO}}'s flagship TV series of the 2010s is ''Series/GameOfThrones.'' Many people subscribe to HBO just to see it. ''Series/TheSopranos'' and ''Series/SexAndTheCity'' preceded this for the 1990s and 2000s.
* Most people know Creator/{{AMC}} as the channel with ''Series/TheWalkingDead'' and ''Series/BreakingBad.'' And maybe ''Series/MadMen''. When people watch AMC, it is to see one of those two or three shows.
* Film making and television has had a few productions that changed how the entire system can be approached.
** ''Film/BonnieAndClyde'' deliberately filmed far away from Hollywood to avoid ExecutiveMeddling, and its success utilizing such violence is what broke UsefulNotes/TheHaysCode forever.
** ''Film/EasyRider'' was made on a shoestring budget, later sold for distribution and became a huge success and the definitive counter culture movie.
** Before ''Film/SexLiesAndVideotape'' film festivals were more about showing classic movies and local talent, afterwards Sundance and Cannes became ''the'' prestigious festivals to showcase your ambitious independent movie.
** ''Series/{{House of Cards|US}}'' revolutionized Creator/{{Netflix}} as producing original programming with A-list actors like Creator/KevinSpacey and Creator/RobinWright, and dropping an entire season's worth of material at once, letting its audience decide when to watch. It made headlines to realize that in terms of numbers it was technically the most watched series in the world. It paved the way for shows on regular TV to go to Netflix and other online streaming sites, including ''Series/ArrestedDevelopment'', ''WesternAnimation/TheCloneWars'' and ''Series/{{Community}}''. And then came a ''second'' killer app in ''Series/OrangeIsTheNewBlack.''
* The original Franchise/{{Superman}} stories were this to comic books in general, turning the medium from 5 cent newspaper strip compilations into an independent and profitable storytelling format.
* Franchise/FantasticFour and Franchise/SpiderMan were '''the''' reasons that kids and teens in the sixties bought Marvel Comics, taking the company from perpetual number two to a legitimate rival for DC Comics.
** For much of the 80s and 90s, Franchise/XMen was Marvel's highest-selling title.
* [[Website/{{Google}} Gmail and Google Maps]] were showcases for AJAX. No one had seen a web page that could be dynamically updated without reloading before. They showed it was possible to build web apps that worked as well as desktop apps did, heralding Web 2.0.
* The Sound Blaster card, introduced in 1989, was not only compatible with the existing Ad Lib card, which already had support for a number of MS-DOS games, it also supported digital sound. The real clincher was the inclusion of a joystick port, and the necessary proprietary CD-ROM interface connector for hooking a CD-ROM drive up to, back when CD-ROM drives required a proprietary connector[[note]]and the only other option was an extremely pricey SCSI card with SCSI CD-ROM drive combo, since IDE CD-ROM drives didn't exist at that time[[/note]]. This meant that only one card was needed to turn the boring, business-focused UsefulNotes/IBMPersonalComputer into a game machine. Combined with the then-new VGA graphics standard, it was also an UsefulNotes/{{Amiga}} killer, at least in the U.S. While the card was quite popular among PC gamers around the turn of the decade because the addition of music and sound made the games that much better than the old PC speaker, the card needed a killer app on its own. PC buyers weren't exactly keen on playing games on a joystick and the price wasn't really tempting. It wasn't until Myst was ported to the PC that the card, along with a CD-ROM drive, became a standard feature in [=PCs=]. The Sound Blaster itself was soon made obsolete thanks to clones, IDE (later SATA) CD-ROM drives, [=DirectX=] and generic sound chips from a myriad of semiconductor manufacturers, but that's another story.
* In the 50s and 60s highways/motorways proved to be examples of this trope for 6-(Europe) or 8-cylinder (America) sedans. Before them, the roads were either speed-limited or too bad for geting the cars to top speed, so customers who weren't buying their cars for racing stuck with 4-(Europe) or 6-cylinder (America) cars. But motorways/highways were places where drivers were able to legally get their cars to their top speed, so that the benefit of having a bigger engine became noticeable.
* ZFS a super-fast, super-reliable file system developed by Sun Microsystems before it was gobbled by Oracle, is one for [[UsefulNotes/{{Unix}} FreeBSD]] and specifically a derivative for file servers called [=FreeNAS=]. Licensing issues [[ScrewedByTheLawyers prevent ZFS from being used with Linux]] but the [=BSDs=] are a lot more permissive about open source licensing that ZFS can be integrated just fine.
* Turbocharging and direct injection served that function for diesel engines in the 90s. Previously, those engines were fuel-efficient, but severely underpowered and because of that, not really fit for passenger cars. The aforementioned technical advancements made diesels more powerful, while keeping the fuel economy better than in petrol engines and making diesel engines viable alrernatives to gas-powered ones.
* Creator/AntennaTV, a digital subchannel showcasing in classic TV from TheSixties to TheNineties, wasn't really well-known until it purchased the rerun rights to Johnny Carson's old ''Series/TheTonightShow'' episodes; they were then rewarded with 26 new affiliates and now share with Creator/MeTV the distinction of being ''the'' classic TV digital subchannel. Digital subchannels like Antenna TV have sparked a resurgence of interest in over-the-air TV programs, particularly among "cord-cutters" trying to avoid paying through the nose for satellite and cable TV programming.
* ''VideoGame/PokemonGo'' is cited as the cause of a sudden spike in smartphone sales in several countries. Additionally, it is also often cited as the main reason "power banks" (external battery packs) are now selling like hotcakes.
* FM radio really only took off in the U.S. in the 1960s when FCC regulations forbade AM radio stations from simulcasting on FM. At the time, most FM radio programming consisted of classical music, Muzak-style background music and "educational" stations that later evolved into Creator/{{NPR}}. Scrambling for content to fill airtime, they turned to PsychedelicRock, where fans of the music appreciated the sound quality and the ability to hear music that wasn't played on the Top 40 of the era. By the '90s, almost all music stations had migrated over to the FM dial.
* ''WesternAnimation/RickAndMorty'' has become this for Creator/AdultSwim, having reached a level of mainstream success and notoriety in three seasons that most of their other shows haven't. The majority of programming on the block is aimed more towards a niche audience.
** ''WesternAnimation/RobotChicken'' is another one. It's a LongRunner that's been around for at least a decade with no end in sight, and also a CashCowFranchise for the network and it's creators. The show's long-lasting appeal may stem partly from its clever satirizing of every topic under the sun, including properties with large fan bases themselves, (like Franchise/StarWars, Creator/DCComics, LiveAction/TheWalkingDead, etc.), as well as it's gorgeous stop-motion animation.
* [=NetBSD=]'s support for a dizzying array of hardware platforms and more liberal licensing terms of the BSD license compared to the GPL that allows developers to keep any modifications proprietary has made it popular for embedded systems development. There's a good chance your Wi-Fi router is running it right now.
* The [=iPhone=] spurred the growth of [=HTML5=] because of something that it ''didn't'' run: Adobe Flash. Web developers rapidly moved to [=HTML5=] and hastened the death of Flash.
* ''Series/MarriedWithChildren'' was the killer app that let the Fox TV network break into the Big-Three-Plus-PBS channel roster that had dominated American broadcast television for decades, paving the way for CW and the countless specialty-networks that would proliferate with the rise of cable.
* Fitness was the killer app for wearable devices. Hyped up as a game-changer in the early '10s that would be the Next Big Thing in tech after the smartphone, it ultimately turned out that most people weren't willing to spend hundreds of dollars on devices that not only looked fairly dorky (the Google Glass was a notable bust), but didn't do much that their smartphones couldn't do, and in fact needed their smartphones to do much of anything beyond tell time. Until somebody realized that you could easily use a smartwatch to measure one's heart rate, in a way that you couldn't do with a smartphone by itself. These days, most owners and users of smartwatches use them for fitness and medical purposes, to keep track of how many calories they're burning as they work out, and most smartwatches are designed with this in mind to the point where many are explicitly marketed as "fitness devices".