History Main / DropInDropOutMultiplayer

In most video games, multiplayer is a matter of choosing the number of players at the start, and then getting a game going. This can be a problem if someone wants to join later. For example, have you ever been playing a game alone that you and your sibling both enjoy, when they suddenly walk into the room and want to play too?

In most video games, multiplayer is a matter of choosing the number of players at the start, and then getting a game going. This can be a problem if someone wants to join later. Have you ever been playing a game alone that you and your sibling both enjoy, when they suddenly walk into the room and want to play too?

The solution to that problem is Drop-In-Drop-Out Multiplayer. The ability to join at any time, and just as crucial, the ability to leave at any time (which helps you avoid that annoying problem where your younger brother suddenly doesn't want to play anymore, leaving with a second character just standing there). These titles have no real distinction between single and multiple-player games, since those initiated as one type can easily turn into the other and back.

This solves more than just the sibling problem – it's also is what makes games with large player limits practical. The GameLobby system, which requires players to get together ahead of time in a group and start the game all at once, would simply never allow for such games to happen by itself.

* ''VideoGame/Left4Dead'' has four characters at all times, regardless of number of players. Joining the game means controlling one of them, leaving means switching them back to AI control.
* A lobby host in ''VideoGame/PAYDAY2'' can allow or disallow both this (the drop-in part, at least) ''and'' [[VideoGameAI AI-controlled]] allies.
* The ''VideoGame/{{Lego Adaptation Game}}s'' do this. They typically have a second character following the first player around, and any player who joins instantly takes control of the second character. Quitting the game means that character becomes AI-controlled again.

* ''VideoGame/RockBand 3'' introduced the ability for players to drop in/drop out at anytime, even during mid-song.
* Playing as Sonic and Tails in ''VideoGame/SonicTheHedgehog2'' or ''VideoGame/Sonic3AndKnuckles'', a player could grab the second game pad at any point to control Tails, while if there wasn't any input for about 30 seconds, the game will start controlling Tails again.

* ''VideoGame/{{Sword of the Stars}}'' even allows players dropping out to leave the AI some basic instructions on how to run their empire and password lock their slot, in case they intend to come back and retake command later.

* ''VideoGame/KirbysReturnToDreamLand'' allows players to drop in and out during levels. They can simply press the + button to join, or push and hold the - button to drop out.

* ''[[VideoGame/{{Civilization}} Civilization 4]]'' had this, though it was a real pain coming into an AI civ where you didn't know where all your units were and had to immediately fortify them all.
* ''VideoGame/TeamFortress2'': allows players to come and go; some servers will even populate "empty" slots with AI bots so that even a handful of humans can still play a (somewhat) meaningful round. In addition, an autobalance and team scramble system is kept in place so that no one team is ever severely handicapped by mass quitting or one side repeatedly curb-stomping the other. Some servers disable one or both of these aforementioned systems, which plays hell with game balance as one side is left with only 4 or 5 players while the other has 12 or more, leading to a curbstomp battle with no one wanting to join the losing side.
* ''VideoGame/FortuneStreet'' has the "Out To Lunch" option, where a player can take a break from playing and a computer AI will take over until the player opts back in. Notably, earning points allows you to purchase personality traits and roles to assign to your Mii that also determine the AI's general strategy. This is an unusual form of drop-in, drop-out in which existing players can leave and return, as opposed to new players joining.
* ''VideoGame/GearsOfWar'' didn't have this at all. ''2'' added it to campaign co-op (with a bot replacing Dom). ''3'' added it to campaign co-op (with bots replacing your other 3 party members) as well as versus multiplayer. It is also possible to join a Beast or Horde game mid-stream, but it requires joining a friend's game through the X-Box menu.
* The ''VideoGame/TalesSeries'' usually enables this. Pause the game to set player 2 as controllable, then play. If you so choose, you can even make every character controlled by the AI.
* ''VideoGame/SinAndPunishmentStarSuccessor'', after a fashion. Since Player 2 is simply an on-screen cursor and cannot take damage, and there is no MultiplayerDifficultySpike, the second player can stop playing at any time without worrying about causing serious problems for the first player.
* ''VideoGame/DarkSouls'' gives players the option to briefly pop into another player's world as a phantom, either to assist them (which lasts until either the phantom leaves, the player defeats the boss of the area they're in, or either of them dies) or to invade and kill them. The brief nature of these excursions means players don't have to devote a large chunk of time to the multiplayer aspect. On the downside, it also means the game [[BladderOfSteel has no pause function]].
* ''Videogame/StarRuler'' and ''Videogame/StarRuler2'' allow players to take over AI empires. If a player drops out, the AI takes over, but the player can return and take over the AI's control.
* ''[[Videogame/MechWarrior MechWarrior Living Legends]]'' allows players to enter a match at any point. The progression-based gameplay means that a player joining halfway through the (usually 30 to 80 minutes) game may have to fight heavy battlemechs while in a basic light mech, but the ComebackMechanic introduced in the [[ScrewedByTheLawyers final update]] and players giving money to each other can get someone up to speed quickly.
* ''VideoGame/DragonsCrown'', being a GenreThrowback to the HighFantasy BeatEmUp arcade games of old, naturally employs this. You could even set it so that AI-controlled characters could randomly join during a dungeon crawl if there's still an available player slot.
* If a local player turns on a controller in ''VideoGame/LittleBigPlanet'', the game asks them what account they want to log in as, and once they pick, they spawn out of the next checkpoint. Online players asking to joins prompts the game to ask if you want them to join, using Triangle for yes and Circle for no. Local players can turn off their controller, and their Sackboy will sit down and leave the game after about 10 seconds. Online players can just leave, or be kicked if you so desire.
* Normally played straight in ''VideoGame/{{Overwatch}}'', but averted in Competitive Mode, where players that leave, voluntarily or otherwise, cannot be substituted. If the cause is a disconnect, they have 30 seconds to reconnect before they're booted from the match altogether, and even then they can only reconnect up to two times. Additionally, if they don't come back, players are allowed to leave with a loss but without quit penalties, as a team that's down by one (out of six) is probably going to lose anyway.
* One of the biggest overhauls new to ''VideoGame/MonsterHunterWorld'', the fifth entry in the ''Monster Hunter'' series, is the addition of the SOS Flare system. If you're having trouble against a tough monster, send out an SOS Flare to invite other players into your quest.

In most video games, multiplayer is a matter of choosing the number of players at the start, and then getting a game going. This can be a problem if someone wants to join later. Ever have that situation where you're playing a game alone that you and your sibling both enjoy, then suddenly s/he walks into the room and wants to play?

[[caption-width-right:"Come on, Blue Toad! We don't have all day."]]

[[caption-width-right:"Come on, Blue Toad! We don't have all day."

* ''[[VideoGame/FortuneStreet]]'' has the "Out To Lunch" option, where a player can take a break from playing and a computer AI will take over until the player opts back in. Notably, earning points allows you to purchase personality traits and roles to assign to your Mii that also determine the AI's general strategy. This is an unusual form of drop-in, drop-out in which existing players can leave and return, as opposed to new players joining.

* ''[[VideoGame/ItadakiStreet Fortune Street]]'' has the "Out To Lunch" option, where a player can take a break from playing and a computer AI will take over until the player opts back in. Notably, earning points allows you to purchase personality traits and roles to assign to your Mii that also determine the AI's general strategy. This is an unusual form of drop-in, drop-out in which existing players can leave and return, as opposed to new players joining.

* ''VideoGame/DarkSouls'' gives players the option to briefly pop into another player's world as a phantom, either to assist them (which lasts until either the phantom leaves, the player defeats the boss of the area they're in, or either of them dies) or to invade and kill them. The brief nature of these excursions means players don't have to devote a large chunk of time to the multiplayer aspect.

* A lobby host in ''VideoGame/PAYDAY2'' can allow or disallow both this (the drop-in part, at least) ''and'' AI-controlled allies.

-->''[Shaun sits down and picks up a controller]''
-->'''{{Announcer|Chatter}}:''' Player Two has entered the game!
-->'''Ed:''' Ain't you got work?
-->'''Announcer:''' Player Two has left the game!
-->''[Shaun puts down the controller and walks off]''
--->-- ''Film/ShaunOfTheDead''

* A server host in ''VideoGame/Payday2'' can allow or disallow both this (the drop-in part, at least) ''and'' AI-controlled allies. Unlike in ''Left 4 Dead'', only two AI players appear in a heist, although up to four human players can be in one.

--->--''Film/ShaunOfTheDead''

-->'''{{Announcer|Chatter}}:''' Player One has entered the game!

* Starting with ''VideoGame/NewSuperMarioBrosWii'', Nintendo's new retro games including ''VideoGame/KirbysEpicYarn'' and ''VideoGame/DonkeyKongCountryReturns'' take the approach of allowing players to join or leave only inbetween levels, but at least it's better than having to set the number of players ahead of time and have it be fixed. The WiiU sequel, ''VideoGame/NewSuperMarioBrosU'', allows players to join mid-game during a level, but not necessarily drop out mid-level.

* The Franchise/TalesSeries usually enables this. Pause the game to set player 2 as controllable, then play. If you so choose, you can even make every character controlled by the AI.

* The ''{{Lego Adaptation Game}}s'' do this. They typically have a second character following the first player around, and any player who joins instantly takes control of the second character. Quitting the game means that character becomes AI-controlled again.

* ''{{Sword of the Stars}}'' even allows players dropping out to leave the AI some basic instructions on how to run their empire and password lock their slot, in case they intend to come back and retake command later.

* In ''MindJack'' if you allow your game to be open other players can "hack" into your single player game, to help or to hinder.

* ''WorldInConflict'' is one of the few online RTS games that has this, made possible by the fact that it has no base building, so new players join at any time during a match without any gameplay disadvantage compared to players who've been there from the start. They ''do'' have the disadvantage of having less time to score points and the game also penalizes you for joining the already winning team if there are vacancies in the losing team (reducing the maximum amount of units you can field at once).

* ''GearsOfWar'' didn't have this at all. ''2'' added it to campaign co-op (with a bot replacing Dom). ''3'' added it to campaign co-op (with bots replacing your other 3 party members) as well as versus multiplayer. It is also possible to join a Beast or Horde game mid-stream, but it requires joining a friend's game through the X-Box menu.

* Games not particularly suited to this sometimes include aspects of it to deal with shortsighted players, especially games that tend toward lengthy matches. It's quite common, for instance, to see a larger ''BattleForWesnoth'' game where half the factions have been handed over to remaining players, the computer, or spectators.