History Main / DropInDropOutMultiplayer

** ''TimeCrisis 2'' and its successors allow you to lock out other players by selecting the Solo Play mode.

* ''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/MarioParty'' games allow you to set human players to computer players and vice versa at any time except during cutscenes and minigames.

* The ''GuitarHero'' series introduced Party Play in ''Guitar Hero 5'', which allowed players to play as many songs as they like with the option of any player to pick any instrument and drop in when they like. When players join, the interface adjusts to fit more players on the screen, and when players leave, their note chart disappears.
* ''RockBand'' ''3'' introduced the ability for players to drop in/drop out at anytime, even during mid-song.

* ''[[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 120 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/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 or is killed, or the player defeats the boss of the area they're in or dies themselves) 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.

* ''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 or is killed, or the player defeats the boss of the area they're in) 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.

* ''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 or is killed, or the player defeats the boss of the area they're in) or to invade and kill them.

The solution to that problem is DropInDropOutMultiplayer. 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.

* Coin-op arcade machines (and many franchises originating from them like ''{{VideoGame/Gauntlet}}'') will traditionally have “PLAYER 2 INSERT COIN” flashing perpetually over the upper right corner of the screen where [=P2=]'s HUD goes, so that just dropping a bit of lucre into the corresponding slot will let any passerby join the game. This is especially useful with titles like the 6-player ''VideoGame/{{X-Men}}'' arcade game. It's generally wise to ask players before joining in, out of courtesy.

** ''VideoGame/{{Darius}} Burst Another Chronicle'' supports up to 4 players, but can be put into "Private Mode" to disallow new players.

* Coin-op arcade machines (and many franchises originating from them like ''{{VideoGame/Gauntlet}}'') will traditionally have “PLAYER 2 INSERT COIN” flashing perpetually over the upper right corner of the screen where [=P2=]'s HUD goes, so that just dropping a bit of lucre into the corresponding slot will let any passerby join the game. This is especially useful with titles like the 6-player ''VideoGame/{{X-Men}}'' arcade game.

* Coin-op arcade machines (and many franchises originating from them like ''{{Gauntlet}}'') will traditionally have “PLAYER 2 INSERT COIN” flashing perpetually over the upper right corner of the screen where [=P2=]'s HUD goes, so that just dropping a bit of lucre into the corresponding slot will let any passerby join the game. This is especially useful with titles like the 6-player ''VideoGame/{{X-Men}}'' arcade game.

* ''VideoGame/SinAndPunishmentStarSuccessor'', after a fashion. Since Player 2 is simply an on-screen cursor with no physical body that can 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.

* ''Rock Band 3'' introduced the ability for players to drop in/drop out at anytime, even during mid-song.

* ''[[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,a dn had to immediately fortify them all.

* 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. In addition, ''VideoGame/KirbysReturnToDreamland'' allows players to drop in and out during levels.

* ''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 system is kept in place so that no one team is ever severely handicapped by mass quitting. Some servers disable this last feature, 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.

* Playing as Sonic and Tails in ''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.

* The 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.

* ''{{Diablo}}'' is almost MMORPG-like, with players able to join and leave at will, form into parties, and the game even applying DynamicDifficulty to compensate for the extra players.
* ''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.

* ''VideoGame/TeamFortress2'': allows players to come and go; some severs will even populate "empty" slots with AI bots so that even a handful of humans can still play a (somewhat) meaningful round.