[[quoteright:360:[[VideoGame/{{Ikaruga}} http://static.tvtropes.org/pmwiki/pub/images/ikar00ga.jpg]]]]
[[caption-width-right:360:Yes, those hands belong to the same person.]]
A SelfImposedChallenge in two-player games in which you play both players at once.

Actually makes things easier in {{Light Gun Game}}s as you can simply [[GunsAkimbo dual-wield]], but harder in games where each player controls an on-screen character, as well as games in which you use StockControlSettings.

A variation of this are ToolAssistedSpeedruns which complete two (or more) games ''using the exact same input sequence''.

Compare TeamworkPuzzleGame.

'''Since this SelfImposedChallenge can be done on virtually any multiplayer game, examples will be limited to games that offer a doubles mode and thus recognize it, or games where this style of play gets enough attention.'''
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!!Games that offer a specialized "double play" mode:
* Most of the Bemani series as well as some other {{Rhythm Game}}s, though the double-play modes present in most of the games offer specialized charts. Examples include ''VideoGame/DanceDanceRevolution'', ''BeatmaniaIIDX'', and ''InTheGroove''.
** ''BeatmaniaIIDX'' allows you to play Double Battle mode, in which you can play the same single-player chart ''on both sides.''
** ''PumpItUp'' has the Freestyle and Nightmare difficulties, which are double-play difficulties. Unlike in DDR and ''InTheGroove'', where double mode is typically seen as an optional challenge, if you're a very skilled ''Pump'' player, you're ''expected'' to be able to play Freestyle and Nightmare.
** ''VideoGame/AudioSurf'' has the Double Vision (not to be confused with one of the [[WebVideo/TheAngryVideoGameNerd AVGN's]] 2-Part episode). It comes in three flavors: Casual, Pro, and Elite, which are Easy, Normal, and Hard, respectively. It was even intentional to be either Two Players or DoublePlay, as it says on the description: ''There are two cars to control. '''Play by yourself''' or with a partner.''
** ''VideoGame/GuitarHero 5'' has Just Dance by LadyGaga available for download, it has no strummed notes and thus both guitar and bass can be played at the same time.
** In both ''GuitarHero'' and ''RockBand'', it's possible to sing and play on an instrument controller at the same time, elaborated below.
** It's very possible to play Versus by yourself on ''VideoGame/DanceDanceRevolution'' with reasonably easy charts that have no or few jumps. You have to spread your legs out three panel widths and every step ends up being a jump.
*** You'll have to get creative in how you hit any pair other than up-down.
*** 3rd mix featured Unison mode, which is meant for two players. There is just one set of "guide arrows" in the middle of the screen, and the arrows are color-coded (red = 1P, blue = 2P, yellow = both), but you can hit the other player's steps. It should be pretty easy to see where this trope comes into play.
* ''VideoGame/{{Contra}} 4'' contains ports of the NES versions of ''Contra'' and ''Super C''. Due to some limitations, if you choose their respective 2-player modes, you'll find that they aren't really 2-player modes so much as this trope.
* ''Raiden III'' and ''IV''. Interestingly, you can configure the controls to control both ships with one controller, or if you're feeling exceptionally coordinated, ''with separate controllers.''
* ''Target Terror Gold'''s Justice Mode allows you to use both guns on a single credit.
* While there's no official mode for it, the loading screens in RockBand suggest playing an instrument while doing vocals, and the vocal harmony feature introduced in ''Music/TheBeatles: RockBand'' outright encourages as many players as possible to multitask at the same time.
** Performing bass and vocals simultaneously is generally referred to as [[{{Rush}} "Geddying"]] [[FanNickname in the fandom.]] Of course, now that a keyboard peripheral has been introduced, it's possible this term could be expanded to players who do [[UpToEleven bass, vocals, AND keyboard at the same time.]]
* ''VideoGame/TheWorldEndsWithYou'''s battle system is a variation of this. For the vast majority of the game, you control both characters, with each character having its own screen. You can have a CPU help you out with the top screen if you're not coordinated enough, though the CPU sometimes does some not-so-intelligent moves. [[spoiler:In one non-tutorial instance of you only having one character to use in battle, you can't do anything but escape, and in the other instance, your three possible partners are being held captive by the FinalBoss.]]
* ''VideoGame/HouseOfTheDead: Overkill'' offers you a dual-wield mode after you've cleared the game's Director's Cut mode. Do an entire level in it and it opens the last few unlocks.
* It is actually possible to double-play a co-op race in VideoGame/MarioKart Double Dash, due to the game having two people in carts rather than one; the process involves holding the driver's controller on top of the rear guy's and playing as if it is one huge, complex controller. While the nature of this setup makes getting mini-turbos and aiming items much more difficult; having the ability to punch rivals - spinning them out AND stealing their items, the ability to nudge yourself using said punch to avoid hazards, and a stronger starting boost when both controllers are timed correctly practically makes up for it.
* The game ''Uberschizoid'' on XBLA has this mode (uberschizoid mode). The blue ship is controlled using the left stick and the orange ship is controlled by the right one in this mode. Due to the nature of the game, however, this game may actually be easier to play in dual mode than single mode once the control feels natural.
* The Target Shooting game in ''WiiPlay'' lets you use two Wii Remotes simultaneously in single-player mode.
* ''VideoGame/MarioParty 7'' has an 8-Player mode in which two people share a controller for certain mini-games, making this not terribly difficult to pull off.
* ''NiNoKuni'' has the Trial of Friendship, a rare ''mandatory'' example of a DoublePlay challenge during a game's plotline. You control both Oliver and Esther (one with the left stick, one with the right) in a top-down maze of falling playforms over a pit. If either one of you falls, you have to start again. You're also under time pressure. If you don't think that's crazy enough, sometimes the characters' paths ''criss-cross''. [[DamnYouMuscleMemory Good luck remembering which stick goes to who when that happens.]]
** Later on the challenge becomes an optional minigame at the Casino, but [[ThatOnePuzzle most players would rather never having to do it again.]]
* Budget light gun game ''Johnny Nero Action Hero'' offers a dual-wield mode. It takes two players' worth of credits, but lets both guns draw from the same ammo pool (so reloading one reloads both and you can effectively use one gun with double the capacity). More traditional dual-wielding (with each gun being a separate entity) is done by choosing 2 player mode instead.
* Done in ''Creator/WilliamsElectronics''[='=] ''Pinball/{{Joust}}'' pinball machine, which has two symmetrical playfields facing each other. This trope is invoked when playing a one-player game, which requires operating both sets of flippers simultaneously.
* The Steam version of ''VideoGame/{{Ikaruga}}'' has a Double Play mode which makes it possible to control both ships with a single controller.
** Pictured above is an ''Ikaruga'' player doing a double-play run. What makes that one especially notable is that he does a no death, S++ rank game all the way up to partway through the ''final boss''. Watch it [[http://www.youtube.com/watch?v=5ZEGyrEnXrk here]].

!!Notable examples of Double Play in other games:
* ''Videogame/TetrisTheGrandMaster 2 PLUS'' has a Doubles mode that is intended for two players in which both sides share one field and must cooperate to reach level 300. Some players have completed it [[http://www.youtube.com/watch?v=n4q1R99ybgs solo]].
* In ''Bub & Bob'', a {{Mac}} clone of ''VideoGame/BubbleBobble'', the level layouts are the same but the gameplay is slightly different. One consequence is that on Level 99 (the last true level; Level 100 is a boss fight) the two halves are completely separated, so you ''must'' use both players. However, since you can call the other player into existence at any time, it's easy for a solo player to DoublePlay this level without having to DoublePlay the entire game.
** More to the point, ''all'' versions of ''VideoGame/BubbleBobble'' give you a BadEnding if you complete the game without a second player.
* A very odd variant that practically counts as a SugarWiki/MomentOfAwesome is a simultaneous tool-assisted speedrun of ''[[VideoGame/MegaManClassic Mega Man]] [[http://tasvideos.org/871M.html 3, 4, 5 and 6]]'', or ''VideoGame/MegaManX [[http://tasvideos.org/1894M.html 1, 2 and 3]]''. The player is using the same controller inputs perfectly synced for all the games. If you pay attention to only one game, [[SugarWiki/FunnyMoment some moves will seem silly...]]
** There's now also one for ''Franchise/SuperMarioBros [[http://tasvideos.org/1778M.html 1, 2-Japan, 2-USA, and 3]]''.
** Speaking of ''VideoGame/MegaMan3'', there's a pseudo-example of this in the form of a couple of cheat options in that game that require input from Controller 2.
* In SuperSmashBrosBrawl, it is possible to use a single GameCube Wavebird controller with multiple receivers to control multiple characters, almost in the style of the Ice Climbers.
* ''{{DJMAX}} Technika 2'''s Duo Mixing mode, in which two players play on a single, split-up touchscreen, has been played solo countless times. The game itself even proposes doing this.
* This is very easy to do in the PC version of ''VideoGame/Sonic3AndKnuckles'' (or using {{emulation}}) when playing as Sonic and Tails as only one hand is needed to control each character. Because of Tails's invulnerability and ability to fly wherever you are if he goes offscreen or dies, you just have to focus on keeping Sonic alive.
* At least one person has done a [[http://www.youtube.com/watch?v=0sHK65IOn5M Quadruple Play]] of ''VideoGame/DonkeyKonga''.
* ''{{Gradius}} Gaiden'' has been double-played. On ''[[http://www.youtube.com/watch?v=L50JxnHcIqI&feature=related Hardest]]''.
* VideoGame/WorldOfWarcraft invented 'multi-boxing', which involves one player playing up to 5 separate characters at once and making leveling a breeze. Blizzard endorses this, probably because it also means you need [[MoneyDearBoy pay for]] [[ScrewTheRulesIHaveMoney 5 separate accounts]].
** If by "up to 5" you mean [[http://geekologie.com/2008/10/guy-plays-36-world-of-warcraft.php "as many as 36".]]
** Also done in [=MMO=]s well prior to WoW [Everquest, for example], and even [[MultiUserDungeon [=MUD=]s]].
* [=JoshTigerheart=] suggested the [[InvertedTrope inverse]] as a solution to people complaining that ''EscapeVelocity'' should have multiplayer: Have one guy controlling your ship's maneuvering, and the other guy manning the guns, or however you wish to arrange it.
* A popular stunt on ''TaikoNoTatsujin'' is to play both drums on the machine at the same time, using one drumstick on each drum. [[http://www.youtube.com/watch?v=t-GaCUcIz2w Click here for an example.]]
* Taken [[UpToEleven Up to Thirty-One]] by [[http://www.planetrea.com/reath/index.html Planet Reath]], a ''VideoGame/{{Civilization}}'' fan fiction / WorldBuilding exercise where the player is controlling all of the civilizations in the game himself.[[note]]And we do mean ''all'' of them. He even downloaded a fan-created patch that allows him to circumvent the normal player limit on hotseat games simply so he could have every faction in the game available.[[/note]]

!!Double Play ToolAssistedSpeedruns
* [[http://tasvideos.org/1555M.html Final Fantasy 5 and 6]]
* [[http://tasvideos.org/871M.html Mega Man 3, 4, 5, and 6]]
* [[http://tasvideos.org/1894M.html Mega Man X, X2, and X3]]
* [[http://tasvideos.org/2636M.html Super Mario Bros 1, 1:TLL, 2, and 3]]

!!References to Double Play in other media :
* WebOriginal ''Series/{{Noob}}'' happening mostly in a MMORPG has several [[AltItis players with two characters]]. The reasons fit in several categories:
** Giving the trope a double meaning by playing in two factions : T-Man prior to getting rejected by the top guild of one of the factions, [[spoiler:NazetrÓme and eventually Gaea]].
** Giving CrossPlaying a try ([[StrawMisogynist Omega]] [[EffeminateMisogynisticGuy Zell]] of all people).
** Replacing teammates that have suddenly gotten a tighter schedrule (Sparadrap).
** Just trying someting different (Ystos and Golgotha).
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