Misbegotten Multiplayer Mode

"It's true, I'm afraid. They've gone and included one of those awful multiplayer modes that seem to be all the fashion these days. This means you and some whippersnappers can huddle round your flickering screen and play a few game that I reckon were thrown in at the last minute and will be average at best."

- Cranky Kong, Donkey Kong 64 instruction manual

There are video games designed primarily or exclusively for two or more players. Many video games, however, are really designed for a single player, and become painful with more than one player; other games may merely treat their multiplayer mode as nothing more than an afterthought.

Compare Socialization Bonus, where playing with someone else is actually beneficial.

Action Game

 * In Evolva, there's a multiplayer mode, but it's kind of tacked on: plain deathmatch that allows you to use your characters from the single-player campaign if you like. Also, finding players is somewhat difficult and the best option is to try to find another player via the Internet protocol. The handful of maps aren't bad (the multi-player maps are medium to large in size and include some of the strangest designs of all the maps in the game), but Evolva multi-player is mostly an afterthought.

Adventure Game

 * In amateur game design forums, frequently a new user will bring up the idea of making a multiplayer Adventure Game, such as King's Quest or Space Quest. None of them have, so far, been able to explain how exactly a linear non-replayable puzzle solving game is supposed to work with multiple players.
 * Uru: Ages Beyond Myst tried this, in MMO format. Now the game is free to play.
 * According to lore, after Space Quest 6, Sierra was trying to develop Space Quest 7 into a multiplayer game, multiplayer being the next big thing in the late 90s.

Beat'Em Up

 * Battletoads, as pointed out by The Angry Video Game Nerd. The number of items is not adjusted, the two players can hurt each other very easily, if one of the players dies, both are sent back to the last checkpoint and one of the levels becomes literally Unwinnable because of a glitch in programming. Later Battletoads games for consoles mitigated this a little by offering an alternate two-player mode where the players can't hurt each other.

Fighting Game

 * Rise of the Robots only allows player 1 to play as the "hero" Cyborg, whereas player 2 can choose any of the enemies. Player 1 will die. A lot.
 * Super Smash Bros. Brawl has a lot of two-player action available in it. Some co-op options are well-done; Event Mode, for example, has events specifically tailored for two players, either by altering single-player events or just making new ones entirely. Some co-op features...don't work so well. In the adventure mode, "The Subspace Emissary", the game ends if player 1 is knocked out, while player 1 can go on without player 2 if need be. (Barely justified in that player 2 is just sort of...there, like Tails, who is mentioned further down on this page.) It's still better than a lot of the other co-op modes, though, especially the Nintendo Hard Boss Battles mode; they end in defeat if either player is KO'd.
 * Punch-Out!! for Wii has a head-to-head mode that is regarded as this by many people, though others will argue that this mode is actually a very deep and intense battle of the wits and people are only disappointed that they can't play as King Hippo or Super Macho Man.

First-Person Shooter

 * The multiplayer modes in Painkiller are considered by some to be an afterthought, shoehorned on top of the single-player mode by the publishers' demand...but that didn't stop the Cyberathlete Professional League from choosing Painkiller as their official 2005 World Tour game.
 * The PSP version of the Peter Jackson's King Kong game added a WiFi multiplayer mode: Both of you played the same level in single player, and the person who completed it fastest "won".
 * Sadly, Doom 3. The guns were poorly balanced, the game shipped with almost no multiplayer modes, and the critical part of the engine was its ability to render quality shadows. Of course, every multiplayer gamer ever turns shadow quality down to get performance.
 * What's worse, Doom 3's own copy protection only locked out the multiplayer modes from the game unless the game was properly activated, which might have factored in on the quick demise of Doom 3 multiplayer.
 * The 2009 Wolfenstein. While the previous entry in its series was known for its excellent multiplayer, the new game managed to completely ignore the majority (if not all) of the innovations RTCW brought. No wonder, just about every fan of RTCW's/Enemy Territory's multiplayer consider the 2009 game to be a complete joke in this regard. Heck, the team responsible for the multiplayer component getting fired on release speaks volumes.
 * Didn't help that it had graphics downgraded compared to the singlepayer version.
 * Tom Clancy's Ghost Recon was a decidedly difficult and engrossing game in single-player, due to the fact that bullets kill, and you want to keep your teammates alive for future missions. Good tactical placement of each member in the squad (to cover each other and lay down suppressing fire) is paramount, and stealth movement is therefore also very important. Of course, in Co-Op multiplayer mode, coordinating a surgical offensive is far more difficult, but is really pointless because unless all players are rubbish they can often work alone, killing enemies by the dozens whenever they spot them. It really takes the fun out of the game, and even placing hundreds of bots on the map doesn't really change anything.
 * Playing Quake II in co-op with two players is already fairly painful, but becomes almost impossible with three or more players, because the levels are so cramped and killing your friends is stupidly easy. Fortunately, the Competitive Multiplayer modes are much better.
 * Bioshock 2's Multiplayer was Passable unlike some of the examples here, but was still an incredibly obvious afterthought.

Hack and Slash

 * Gauntlet (1985 video game) is a classic arcade game meant to be played with two people, and its sequel with four. The PC port can also be played with four people, if they can somehow all fit at a single keyboard.
 * Some PC arcade sticks emulate keyboards, so that isn't all bad. The game would be tricked into thinking that all four players were using one keyboard, when in reality they would be using four arcade sticks and three buttons each.
 * The first Diablo. Friendly fire. It was still possible until the mage learned Chain Lightning, after which his allies were forced to take cover behind walls every time monsters showed up.

Miscellaneous Games

 * Glider PRO has a two-player mode where the first player to leave a room (Glider PRO is a non-scrolling game) must wait for the second glider to follow, or press a suicide button if it can't. The second-player controls being non-configurable (locked to the modifier keys) is only a minor annoyance compared to this.

Platform Game

 * Many people criticized the multiplayer modes of the two Metroid games so far that have had multiplayer (Metroid Prime 2, which was oriented more towards single-player anyway, and Hunters, which was clearly built around multiplayer).
 * Super Mario Galaxy. The second player... can stop enemies! And bother Mario! How awesome! Thankfully averted in the second game, though, where the Co-Star Luma (controlled by player 2) can grab all sorts of items bar the Rainbow Star, and, in addition to freezing foes, also do its own Spin, which is just as effective as Mario's.
 * New Super Mario Bros. Wii is an interesting mix of this and Socialization Bonus. When there are two or more people playing, if one dies but has at least one extra life while the other remains alive, they can be rescued a while later. The characters' heads are also rather good as trampolines, and two small characters carrying each other can break blocks just like their Super versions. More items spawn from "?" Blocks as well. However, more often than not, the players will get in the way of each other, often leading to mis-obtained items, Total Party Kills and much frustration, as any co-op Let's Play can prove.
 * Sonic the Hedgehog 2 and 3 for the Genesis are an odd case. They have multiplayer modes, which are fine, but you can also have 2 players in 1 player mode. Player 1 controls Sonic, while player 2 controls Tails... but if Tails goes offscreen, which happens often, you have to wait until he flies back onscreen and lands. If Tails dies, he comes back the same as if he goes offscreen, but if Sonic dies both player go back to the last checkpoint. And that's only the tip of the iceberg. On the other hand, if you can get someone to play with you during the Special Stages, getting the Chaos Emeralds becomes much easier. The Special Stages work much better with multiple players than the acts do.
 * Shadow the hedgehog bought back this feature where a second player can control the helper characters (minus Black Doom, Eggman, and oddly, Charmy). Not very useful in "get to the goal" missions for the same reasons mentioned above in Sonic 2 and 3. However, instead of having to wait for the helper to re-appear if he/she falls off camera, this game now has the option to call him/her back to your side with a simple tap on the D-Pad, which makes it actually worth it in alternate missions like "collect X rings" or "kill X enemies". For added hilarity, you can use characters in their opossite missions: have fun using Sonic to beat GUN soldiers and then have him complain on Shadow.
 * Donkey Kong Country Returns has a co-op mode which seems to benefit gameplay as both Kongs can move separately AND tag along to use the 1 player version moves. However, due to the Nintendo hard difficulty and that, unlike New Super Mario Bros Wii, players share lives, it can become a hindrance.

Real Time Strategy

 * Brutal Legend had quite good multiplayer - for 1v1. While the game supported teams of up to 4v4, playing team games was often an exercise in futility. There was still only one stage and a shared money pool, which meant that whomever wanted the cheapest unit built "won" the argument. Additionally, having multiple avatars in the vicinity issuing orders confused the bejeezus out of the AI.

Role-Playing Game

 * The original version of Final Fantasy VI for the SNES allowed you to play in two player mode, which just meant that the second player could control a few of the characters in battle. If they happened to be bitter about being made second player, this person could, instead of attacking the monsters during battle, kill the characters assigned to first player, allowing them to take over control.
 * Final Fantasy V also allowed to give control of some characters to player 2.
 * Final Fantasy IX did it too, probably as a throwback.
 * Bethesda Softworks added gratuitous multiplayer mode to the first The Elder Scrolls Spin-Off, Battlespire. They never did it again.
 * Troika, the makers of Arcanum: Of Steamworks and Magick Obscura, were forced to include a multiplayer mode by Sierra. They promptly hacked out a single module and an almost completely unplayable interface, which was promptly laughed at by the fan community.
 * Lord of the Rings: The Third Age had a 2-player mode that was just like the Final Fantasy examples above. Or worse, since your party is only 3 characters in this game, while all the above examples have 4-man parties, so someone is only getting one character.
 * Could be even worse, since although there are six playable characters, when 2-player mode is activated, the game doles out a pre-set selection of characters to a player (Berethor, Hadhod, and Eaoden to Player 1, Idrial, Morwen, and Elegost to Player 2). Thus, it's possible for a single person to be playing on 2-player mode because the other three characters (who are assigned to the other person) are useless for the scenario.
 * Believe it or not, but the early Infinity Engine video games (Baldur's Gate, Icewind Dale) were all geared towards multiplayer as a legacy of their prototype, Battleground Infinity. Said games included multiplayer modes... but nobody remembers that, thanks to them being the major codifiers for the story-driven single-player Western RPG genre.

Shooting Gallery

 * The arcade Shooting Gallery series, Police Trainer. Most of its 2-player minigames are the same as the 1-player variant, or even more difficult simply due to the distraction of shared screen space. Worse, one player may directly cause the other to fail a minigame (and losing precious coinage with it) by being greedy and shooting more targets than required, and a few minigames are directly competitive, requiring someone to fail. Police Trainer 2 was slightly better and even had a cooperative minigame for each rank, but one of its 2-player minigames was outright Unwinnable due to lack of targets for both players, putting a quick stop to the fun.

Survival Horror

 * Dark Messiah's online multiplayer play more like a bad Half-Life 2 mod than anything to do with Dark Messiah, ignoring the singleplayer game's brilliant combat system, spells, classes and with far worse graphics. Of course, it was made by a different company altogether.

Third-Person Shooter

 * Psi Ops the Mindgate Conspiracy is primarily a first person shooter with Psychic Powers. It has a CoOp mode that allows player one to steer and shoot the weapons, and player two to control the psychic powers. Unless both players are on the same page on what to do, things can get very... strange. Considering the dev team had so much trouble assigning buttons they couldn't find a way to fit in rolling or dodging (and thus both are absent from the game), this would be an ideal solution to games with lots of powers... if you had four arms or really good teamwork with player two (but lets be honest, the first is likelier).
 * One game along these lines was the original Mechwarrior on the SNES, in which one player did the steering and the other aimed the turret.
 * Despite the story offering the perfect setup for 2 player coop, the only online multiplayer in Kane and Lynch is a 4-8 player bank robbery mode with no connection to the main story.
 * Console versions of Freedom Fighters had a rather mediocre 2-player Capture the Flag mode that was quite obviously tacked on as an afterthought, using three maps recycled from single-player levels. The PC version left it out altogether.