My first paper dedicated to multiplayer level design tackled the specific constraints imposed by the multiplayer game mode compared with that of single player. Later, my second paper detailed the level design rules that I consider to be the most important to respond to these constraints. Today, I will tackle another equally important aspect of the development, balancing.
Balancing consists of ensuring that no player or group of players can keep the advantage systematically throughout the game, by making the most of a game parameters (the power of a weapon for example) or of a weakness in the map. This problem is particularly seen in multiplayer games, because their users have plenty of time to discover the faults of the game and exploit them to their full effect. As maps are played for tens of thousands of sessions and players easily swap tricks among themselves.
A fault in a map could potentially kill the entire map by enabling a player or a group of players to reach a highly destabilizing advantage. That very problem was raised in one of the multiplayer maps we developed for Splinter Cell - Pandora Tomorrow's Warehouse. In this map, divided into three areas, the killed defenders spawn in a small room next to the first play area. This room is obviously reserved to the defenders and the attackers are not supposed to have access to it.
After a few weeks of use, we realized that attacking players had found a technique to enter this room by taking advantage of the moment when one of the defenders walked out of it. As soon as they were inside, they could easily kill the defenders as soon as they respawned! Such a fault could have made the map unplayable. Fortunately, this was not the case, thanks to the fact that the map was divided into areas, because as soon as the mission objective of the first area was reached, the players move on to the next area.
A poorly balanced game ends up making the players lose their interest, because nobody likes fighting against an opponent who benefits from an unbalanced advantage. Note that balancing isn't only about level design, but also the game system and the game design. Three directions must be considered to balance a multiplayer game: the level design itself the game design and the playtests.
The first level design decision that is likely to affect the balancing of a game is the map's size and the number of players it can support. A small map generally makes balancing more difficult, because tiny details are amplified by the density and the speed of the action. Conversely, if the map is too large, the players will get bored because encounters will be rare. The choice of the ratio between the number of players and the size of the map is therefore very important. In most cases, opt for relatively large maps. They offer more tactical opportunities, and it will therefore are more difficult for the players to take advantage of the faults of the map.
The map layout itself can favor the balancing of the game. An open map (outdoors, for example) and the use of the third dimension (see my paper dedicated to map design) will make it difficult for bottlenecks, which could create destabilizing situations, to occur. Such maps offer more tactical opportunities than "flat" indoor maps.
Finally, the map should also offer various opportunities to use the game design features: weapons, equipment, moves, and so on. The maps of the multiplayer versions of Splinter Cell - Pandora Tomorrow and Chaos Theory include many places where an attacker can hide to prepare to ambush a defender, objects to hide behind, high footbridges to supervise a large area and accurately throw grenades, and pipes along the ceiling of rooms used by the defenders which allow the attackers to jump them.