Socialization Bonus

An aspect of the game where you can get additional content or powerups by interacting with other people who own the game. And then there are the games that can only be played in Multi-Player.

Supremely awesome if one actually has access to friends who own the game; a Fan Convention is a great place to do this. Modern consoles and handhelds are able to go online, so many games with these features also include anonymous internet matchmaking.

Supremely annoying if no access is possible due to location, you're replaying an older game that isn't in sync with whatever is popular these days, or you simply don't have any friends. In this case, you might have to buy multiple copies and play with family, give them as gifts, or word-of-mouth advertise to get your friends to buy the game. (This can make some Socialization Bonuses seem more like Revenue Enhancing Devices.)

Compare One Game for the Price of Two, where some games require this for 100% Completion.

Not to be confused with that kind of socialization bonus.


 * If you Gotta Catch Them All in Pokémon, you must engage in this, since not only are the Pokémon divided up between games, but every generation has some Pokémon which only evolve when traded. Also, Pokémon obtained in trades gain experience faster than Pokémon caught in your own game.
 * Another example from Pokémon is the original Mystery Gift, which rewarded players with random items (usually decorations).
 * Then there's the Spiritomb event in Pokémon Diamond and Pearl and Platinum, where you must talk to 32 other players in the Underground to trigger Spiritomb's appearance so you can capture it. And NPCs don't count.
 * Or mail. Always Music Mail.
 * Many of the Pins in The World Ends With You only "evolve" into other Pins if the points gained are from connecting with someone else with either a DS Wifi active, or another TWEWY game, also searching for other players. In theory, one can hope for random "alien" encounters for socialization points, but this would take days in real time to evolve a single Pin this way, days spent not actually playing the game.
 * In fairness, these points are weighted; in absolute numeric value they do nothing extra to level up the pin, but pins evolve based on what type of point comprises the majority of experience on the pin, and the socialization points counted for nine times as much as battle points.
 * There are also several Gatito pins that only work if you have a complete set consisting of several pins. There are only two ways to complete the set: one is through incredibly low-percentage drops on Ultimate difficulty from Bonus Boss fights, and the other is to buy them from stores... which only sell one pin per set per DS. To buy the others, you have to play the game on other DS units.
 * You simply cannot play The The Legend of Zelda Four Swords part of The Legend of Zelda GBA Link To the Past/The Four Swords combination if you don't have other players who have their own GBA systems and copies of the game. Without them, you can at least watch the opening cutscene...
 * Hilariously, two aspects of A Link to the Past cannot be accessed without first completing The Four Swords. The first being the quizlike series of Fed-ex quests to receive an upgraded spin attack, and the second being the Palace of the Four Swords.
 * In celebration of the 25th anniversary of the Zelda franchise, Nintnedo made the Four Swords game for DSiWare to be played with one person if there are no other players to play with. Playing in single player has a 2nd Link tag along who doesn't do anything but follow you and help you set up for executions requiring the actions of multiple players at once and both Links can be swapped should you need to split them up. However, there are several bonus levels that qualify as a Brutal Bonus Level because of the huge amount of enemies that are thrown your way and some are also Elite Mooks, thus you need friends to help you stay alive.
 * Many powerful chips in the Mega Man Battle Network series are only possible via this method.
 * In the Mega Man Star Force games, you can collar extra Link Power by forming "BrotherBands" with other people who own the game in question, allowing you to equip more and beefier abilities and qualify for certain sidequests and items earlier than you normally would. Plus, well, "Hey, guy with Zerker x Ninja! I've got Zerker x Saurian. How 'bout we both get ourselves access to Tribe King?"
 * Star Force 2 had an inversion in the Indie Fragments - using them gives you a variant on your old Super Mode that enhances sword attacks and can never be removed by enemy action...but they take up your six Brother slots, so if you have any non-storyline friends, you have to reject them to access Mega Man Rogue. (As an interesting side effect, it also becomes impossible to use the ability that lets you auto-enter Super Mode at the beginning of combat.)
 * In Final Fantasy III DS, sending a sufficient number of mail messages to other owners of that game via the Nintendo DS e-mailer unlocks the Lethal Joke Character class and extra dungeon.
 * This is what makes Rock Band fun, as the main meat of the game (the Band World Tour) is only accessible in multiplayer. The more players, the better.
 * Though if you are a decent singer (or settle for the lower rewards of lower difficulties), you can play any instrument while singing yourself. It's hard, but also epic awesome.
 * Rock Band 2 reduces the impact of this trope in some ways (offering single-player career-like "challenges"), but improves it in other ways (said challenges are easier with a band to help correct your screwups).
 * You make it sound like the Tour Challenges are the only option for solo Rock band 2ers. It's not. A solo player can play through the exact same World Tour mode that a multi-player "band" gets.
 * Mortal Kombat: Shaolin Monks, of all games, also has elements of this: some of the secrets are only accessible in co-op mode. None of them are ultimately that essential, though, and generally just consist of artwork.
 * Some Team Fortress 2 achievements (particularly the Medic achievements required for the Infinity Plus One Bonesaw, before the requirements got lowered) require the use of Steam's not-entirely-intuitive Friends list.
 * Then there's the achievement for playing a game with seven people on your Steam Friends list. Too bad if you don't have seven Steam Friends you can get together, or even seven friends.
 * Similarly, many of the Medic achievements needed another player to do something totally counter-intuitive (like a heavy punching people while Ubered), that they effectively required a cooperative partner to help you boost them.
 * While not required, all Creatures games allowed players to save their Creatures as discrete files and give them to friends (or put them in stasis for six generations, or clone umpteen times), and Docking Station introduced the ability to send them over the internet within the game. Additionally, Creatures 2 was somewhat backward-compatible, allowing creatures from the first game to be converted for the second.
 * zOMG! places a heavy emphasis on socialization. The game is designed in such a way that if you don't find some people to crew with, you're not going to progress very far. In fact, the path to the Final Boss for the launch chapter requires synchronization between at least 3 players to open. In addition, your character gets bonuses by interacting with other players, called G'hi bonuses. You can fill your G'hi up by visiting Barton Town or joining a 6 person crew. But if your G'hi runs out, all of your bonuses will be gone until you can get more G'hi.
 * Most MMORPGs, if not all, require players to work with others to complete the most challenging dungeons. World of Warcraft and most MMORPGs with a crafting system make socialization necessary to access most crafted equipment by limiting the number of crafting skills a single character can take.
 * In the earlier days of Final Fantasy XI, if you wanted nearly anything done, you needed a party. A major reason people left FFXI was simply because there were times where you could do nothing but wait for a group. Missions? Party. EXP(That didn't take forever)? Party. Quests? Party. Get unsellable gear from a Bonus Boss? Party. The things you could do on your own were very limited, and most of them only possible at the cap of level 75. Nowadays, there's a lot more solo content, but most things still require more than one person to do.
 * It is apparently also still a problem if you chose to become an undesirable class. Are you a Red Mage? People will practically pay you to join their group. A Puppeteer? You might as well give SE another dollar so you can start over.
 * Super Smash Bros.. Melee has Mewtwo, who is unlocked by playing Vs. mode for 20 hours. However, each vs. match counts for every human player involved, meaning that having more players unlocks Mewtwo faster.
 * However, the 20 hour requirement can easily be bypassed by having the game being played in a timed match with the clock set to infinite. Leave the game running until the 20 hours have passed.
 * Crafting in Kingdom of Loathing. The best foods are Hi Meins. Creating them is a three-step process, each step requiring the level 15 skill of a different class. The last step actually requires that you be a Mysticality class, so skill perms won't help you there.
 * There are also Hobopolis and the Slimetube which require you to be in a Clan in order to play in them, and while it is possible to get the best rewards in Slimetube by yourself You'll want a team of 6 people in order to find the best items in Hobopolis.
 * And the mall, as well as trading in general. Honestly, despite the label of an MMORPG, Kingdom Of Loathing is a single player game with a few socialization bonuses.
 * In Boktai, the Azure Tower contain the strongest of each type of Gun Frame, but you can only get ones that you have the proper seal for, with there being seven total (for each of the elements in the game). With one cartridge you're only given the Dark seal in the New Game+, the Sol seal after growing the Solar Tree (which takes a couple of hours in direct sunlight), and one random one (out of four) when you enter the tower for the first time. The rest you need to get by linking to someone else. What's worse, only the random one is transferable through this method - even if the other person has all seven, you'll only get one - and if it's the same type, well...
 * Played straight and averted in Little Big Planet. "Acing" a level (clearing it without dying once) is virtually impossible in multiplayer, so certain rewards are essentially locked to solo play. Meanwhile, many segments have multiplayer areas whose rewards require multiple people to solve a puzzle. Up until the Wilderness, this is usually two players - after that, many of them require a team of four. (Thankfully, that always-handy "Play Online" button and good luck with headsets makes this much easier here than in some examples...)
 * Some of the sidequests and Multiple Endings in Resident Evil Outbreak would only work on Multiplayer because of triggered events. Too bad, because there's no multiplayer for those games any more.
 * You could play the original Final Fantasy Crystal Chronicles by yourself, with a Moogle carrying the myrrh bucket for you, but it was far more satisfying to play alongside friends so you could argue over who had to carry the bucket through the level. However, doing this required as many Game Boy Advances and Game Cube-GBA link cables as there were players.
 * Kingdom Hearts 358 Days Over 2 has Mission Mode, which lets you replay completed missions from Story Mode in order to gain Mission Crowns, which can be redeemed for bonuses from the Moogle. In the Japanese version, Mission Mode can only be accessed in multiplayer format, while the American version is more liberal, enabling you to play Mission Mode either with friends or by yourself, though the enemy stats are boosted regardless, making it Nintendo Hard. Still, you do get EXP even if you fail, so you can keep trying until you're strong enough to win. Playing Mission Mode is the only way to obtain the maximum number of inventory slots available, and it is the only feasible way to reach Lv. 100, as the gaps between levels are so wide at the end of the game that playing without level multipliers (some of which are only available in Mission Mode) would qualify as a Low-Level Run.
 * The Camraderie stat in Metal Gear Solid: Peace Walker.
 * Runescape has (at last count) two quests in which you must team up with other players. The first of these quests assigns you to a gang, so you have to find someone else who is in the opposite gang. You only really need the other player for a few minutes though.
 * Left 4 Dead's AI bots don't have the necessary perception to leave a partner untreated when temporary health is a better option, they can't use any kind of grenades, and they frequently interrupt your shooting by giving you pills or adrenaline at the most inopportune times, and in the second game, they don't collect special ammo or use melee weapons either. They aren't completely incompetent, being able to shoot very accurately and very rarely getting lost, but they're vastly inferior even to somewhat inexperienced human players.
 * In the newer Wii platformers, if all but one player die, they can be resurrected by the one still standing. Makes beating some levels MUCH easier, and maybe even necessary.
 * With the SpotPass and StreetPass features of the 3DS, Nintendo has integrated this trope into a system itself rather than a game.
 * Mario Kart 7 uses the StreetPass feature to unlock the Gold Glider part. The more people you connect with the feature, the less coins you need to unlock the part. Don't live in a place where lots of people own a copy of the game and use the StreetPass feature? Have fun grinding for 10,000 coins to get that Gold Gilder.
 * Many Xbox 360 games from the first two years had achievements that required local co-op (before Xbox Live play became basically universal), notably Guitar Hero II, in which 1/5th of the game's achievements were based on local co-op.
 * Guitar Hero III had the same co-op of Guitar Hero II (second player plays bass/rhythm guitar). That, alone, isn't bad at all. What makes it bad is that it introduces co-op career mode that must be played with two players, and said mode includes six songs that aren't unlocked in the course of single-player mode or the unlock shop (though, mercifully, a cheat code is available that unlocks everything).
 * Pac-Man Vs., originally bundled with Pac-Man World 2, is only playable in multiplayer and requires one GBA and the special cable.
 * Final Fantasy Crystal Chronicles pushes heavily for multiplayer. While it is possible to solo the entire game, you won't be able to get rare items or be able to cast high tier spells without any friends. The game also doubles as Revenue Enhancing Devices due to the fact that you can't play multiplayer with a standard controller; you need a Game Boy Advance and the GBA-to-GC link cable for each player.
 * Metroid Prime 3: Corruption includes a feature wherein you can use "credit" icons obtained in the game to buy extra stuff. The green credits, however, can't be obtained on your own... you have to have someone on your Wii's friend list send you "Friend Vouchers" that they got on their game (the vouchers are totally useless on your own game.) Players also have to make sure their friend has the same version of the game, otherwise the feature won't work.
 * The PSP remake of Final Fantasy Tactics requires you to link up with another player to do the multiplayer battles that give out some of the uber equipment that could only be gotten via theft in the US version (not the Japanese version) of original.
 * Trauma Center: New Blood can be completed entirely in singleplayer, but having a competent partner in co-op makes some operations much easier: not only do you have a second pair of hands, but you can use both Healing Touches in the same operation.