The Principles of Design
The principles of design are guidelines for proper visual design that is aesthetically pleasing and effective at communicating the intended message to the viewer. In this section, I'll be providing examples of how the principles of design are effectively used in level design in games.
Balance is the state of equilibrium in a design. If a composition is completely balanced, it evokes tranquility and calmness, otherwise it evokes a sense of chaos and confusion. The same term is used in game design for game balance, and the concept is similar for levels and visual design.
Symmetry is an easy way to create balance. Most MOBA/ARTS games like DotA and League of Legends use symmetrical game maps to create near-perfect terrain balance between the two competing teams:
Teams start in either the upper right or bottom left corners of the map, and if you divide the map in half diagonally from north-west to south-east corners, the map is (nearly) symmetrical, facilitating gameplay balance.
While symmetrical balance works in games where both teams share the same competitive objective, asymmetrical maps lend themselves towards game types where one team has a different objective than the other. Gears of War's multiplayer map Escalation is a great example of an asymmetrically balanced map:
In a King of the Hill game type, this map warps the flow of play such that the team that controls the top of the staircase defends the "hill" from players at the bottom of the staircase. While the top team has the advantage of high ground, the low team is provided with sufficient cover and multiple routes of ascension to create a map with a very linear but nonetheless balanced state of play, despite the fact that the map is asymmetrical.
Note that asymmetrical maps can still supplement balanced gameplay. One of the most popular multiplayer maps in Halo 3, Guardian, is an asymmetrical map:
Guardian manipulates line of sight, advantageous weapon placement, and flow and choke points to create a map that is balanced and forces the players to adapt to a different style of play depending on where they are on the map. It takes an enormous amount of level design intuition, and a deep understanding of the other principles of design to create an asymmetrical map that is also balanced. An asymmetrical map that is balanced creates a level that is challenging to understand and strategize and even more difficult to master.