One of the core parts of being a game designer is presenting challenges to players within the environment of a game; few games are designed without any challenging elements, because they are what adds a lot of the feeling of interactivity to games, allowing players the chance to change the story in which their character will fail into one in which they succeed. However, special concerns must be made in order to facilitate a challenging experience in multiplayer games.
The first thing to consider when designing multiplayer challenges is the types of challenge that are being considered. There’s really two types of challenge, symmetrical and asymmetrical challenges, which are crucially different.
A symmetrical challenge will feel the same for every player. Player choice may still play a role in the challenge, but the aspects being looked at are the same for every player, and for the most part success is theoretically possible in all but the most crushing challenges for all players. Most games’ combat is like this; in Dungeons and Dragons a rogue won’t be dishing out the most damage of any party member in a toe-to-toe fight, but they’ll still be capable of stepping up to the challenge and making a good attempt, even if they’re not the best.
In many games, these take the form of pure skill challenges, rather than player decision biased challenges; the lines blur as games grow more and more complex and more preparation is possible, but one of the purest examples would be the competitive “instagib” deathmatch in some multiplayer FPS games; each player will die after taking a single hit from another player’s weapon, eliminating as many environmental and situational modifiers as possible (no getting lucky and finding a high value weapon, for instance). However, symmetrical challenges can be based around player decision just as much-playing a rogue in the example above still allows the player to participate in combat.
Asymmetrical challenges don’t care as much about everyone participating. They’re most common in games with highly defined roles; in Dungeons and Dragons only a rogue (or similar character) will be able to pick tough locks and disarm devious traps, though other characters may be able to display a shallow facsimile of the rogue’s prowess on lesser challenges. Asymmetrical challenges tend to be based on player choice.
As a game designer, weighing symmetrical challenges and asymmetrical challenges is important. Dungeons and Dragons Online intentionally requires certain classes to unlock traps, and somewhat deviously locks AI “hirelings” for party accompaniment in the premium shop, creating a revenue stream, but also makes sure that there are few situations where having a rogue or similarly able class is notably beneficial to the progress of the group; discovering where a trap is should serve a wary party as well as neutralizing it.
When dealing with multiple players, the idea is to create challenges that as many people can participate in as possible, but not punish people for their neighbors’ failures (unless, of course, teamwork is a core game principle, which is often not the case). The classic example of this is linear scaling; in most hack-and-slash games the typical solution to multiple players is to boost the strength and number of foes to counteract the larger group.
Upsides of the linear scaling model are the fact that it can keep everyone engaged, and it’s really easy to do. It can also be hooked into the game’s progression metric to keep the game difficult, though this can cause major balance issues with games with advancement in multiple fields, as seen in TES IV: Oblivion, which had some major issues for those who chose non-combat skills to focus on. However, the linear scaling model isn’t difficult, doesn’t let players feel special, and can simply lead to overdose, especially if the game is particularly fatiguing for players as is (for instance, Borderlands’ cartoon shading effects gave me headaches at times). In addition, the linear scaling model doesn’t encourage teamwork in the slightest; cooperation meets a group goal but there’s no need to collaborate when a simple full frontal assault will take down all the foes.
Player incapacitation challenges are pretty common nowadays as well, appearing primarily in horror games like Left 4 Dead and Dead Space 3, with one player relying on another for help. One player, for some reason or another, is forced out of the normal game experience and requires assistance from the other, often through the form of a minigame, to return to play. This builds a rudimentary sense of teamwork, and can be used to punish misbehavior or add tension (e.g. survivors getting grabbed by a Smoker), but also leads to a break in immersion (sometimes), and can be annoying and aggravating if it happens too often. Most games also include a quick time event or other opportunity for the player to redeem themselves, allowing for a single-player experience that doesn’t become ludicrously difficult or for a player who’s been abandoned by his teammates to survive.
Another model often used is asymmetrical locked challenges. The Lego toys franchise pumped out a whole line of licensed adventure games that essentially gave players a bunch of challenges to meet. This was a little bit of an exception to the rule, since changing characters on the fly was a major part of the game, but it allowed players to experiment with different character roles in interesting and engaging ways. In games that support something like this, additional elements are added to allow players whose characters have special roles to shine; Dragon’s Crown has an element like this with an NPC rogue who can be used to pick locks, DDO has this in the form of player rogues and artificers, and it’s generally something that allows players to feel special. Dead Space 3 actually does this as well, with each character getting special hallucinatory challenges in multiplayer, though this is more a change in feel than a change of gameplay.
Finally, you have asymmetrical role challenges, which focus on providing each player with a radically different experience. These aren’t too common, since they require more development time and usually serve a cooperative experience better than a competitive one, but they’re pretty impressive when pulled off right. For instance, the Arma series has these in droves, albeit in a very loosely structured form, by allowing players to take on the roles of fighter pilots, tank crews, and in the most recent installment underwater divers (and more, of course). While these roles interact entirely with the rest of the game, the skills they require are notably different (you don’t want someone in their first helicopter), and their roles define their experience heavily. Someone defined to a helicopter pilot role will have to master the alternate skills required for flight and also have to cope with the fact that should they survive a crash landing in enemy territory they are usually ill-equipped for the infantry combat the series is so well known for.