Depth and possibility space

You have probably heard about some games being described as deep. Depth in this context means that a game has a lot of complex systems and interesting choices hidden beneath the surface. Remember hearing about games that are easy to learn but hard to master? This cliche refers to a perfect-world scenario in which a game is accessible and understandable, yet filled with intricacies that take years of practice and offer near limitless replay value.

To create a game with a wide possibility space is to create a game with potentially endless combinations of interesting and unique scenarios to explore. Do games like that exist? Wouldn't they require an enormous amount of content to begin with? The answers are yes and no.

Think of classic games such as Chess or Go, these games rely entirely on their elegant rule sets. These rules enable an incredibly deep set of gameplay scenarios that can entertain players for years. There are 20 ways in which you can open up a game of Chess. By the time your opponent responds, the number of possible board states skyrockets to 400—each being more or less a valid and meaningful move. These games rely not on supplying new content but on the availability of interesting move sets and challenging opponents to play against (you can play chess against an AI, but it's arguably much less fun without a human opponent). You can say that, through a wide possibility space provided by the rules, these games have avoided becoming a content furnace.

Does that translate into modern video games? Yes, it does! At the time of writing of this book, I have amassed over 2,000 hours of playtime in DOTA2, Valve's famous MOBA (multiplayer online battle arena), not to mention several years spent playing League of Legends beforehand. In these games, the level design stays largely fixed. It becomes an unchanging avenue for the moment-to-moment displays of skill, short-term decisions, and long-term strategy. These are games that achieve replayability via deep choices and a wide possibility space, an outcome of:

• Interconnected content that creates millions of combinations:
  • A large number of playable characters with unique abilities. Given that these games are played in teams of five, the number of possible team combinations is enormous.
  • A large number of items to purchase in-game that can have a meaningful impact on your character's (and your team's) performance.
• Rules and mechanics that test a variety of skills:
  • Physical skill tests such as timing, aiming, and reaction times
  • Tactics and short-term decision-making, including environmental awareness, item and skill development decisions and enemy movement prediction
  • The long-term strategy, often based on spotting play-patterns and predicting enemy team behavior
  • Communication, coordination, and leadership
• The challenge and satisfaction of playing against human opponents. These games wouldn't be as engaging and popular if they were played against AI opponents. It's incredibly difficult to create effective but seemingly natural AI opponents, and even harder to have them work together and make interesting choices.
• An ever-changing meta—the way in which the game is being played by the community evolves with the game itself. If a certain strategy becomes dominant, the community naturally evolves by learning to expect and counter it.

I am just scratching the surface of what makes these two games replayable, though now you may be wondering do I need 100 items and 100 characters to create a replayable game? The short answer is no, you don't! The slightly longer answer is, look at games such as Rocket League—a game that could be described as football played with cars. The rules and victory conditions are simple and elegant: get the ball to the enemy goal by hitting it with your car. The amount of content required for this gameplay to work is impressively small—one arena, one car, a boost pad, and a ball. The game is played in small teams (from 2 to 4 players per team), where each player controls a single car that drives in a familiar way, but players can also jump and steer their car in the air and use a rocket boost to propel themselves. Hit the ball with your car and try to get it to the opponent's goal and… that's it! Simple, right? Yet, for many, the replayability is through the roof! The way Rocket League achieved its elusive easy-to-learn, hard-to-master status is all down to the simplicity of the rules paired with the incredibly high skill ceiling of precisely controlling the movements of your car in relation to the ball and each of the surrounding players. It's a highly kinetic game where great timing and team play are absolutely essential.

Even though the human factor can hugely help in providing fresh challenges, depth and a wide possibility space are not exclusive to multiplayer arena games. Think of strategy games such as Sid Meier's Civilization and the Total War series, or simulations such as SimCity and Dwarf Fortress. One could argue that even if you removed most of the visual assets and reduced the amount of content, the effect of interactions between the player and the systems powering the game could still provide dozens of hours of fun, filled with interesting decisions and engaging outcomes.

Creating deep games is a very difficult craft and can take more time and expertize than crafting heaps of content surrounded by more shallow mechanics. As you increase the number of combinations and possibilities within your core gameplay mechanics, you expose your systems to a range of extreme (and potentially game-breaking) scenarios. Before you add any new rule or feature in the hopes of extending the game's lifespan/depth/complexity, your team will need to make a set of important decisions. Widening the possibility space can (and almost surely will) bring currently unforeseen consequences. Will you have the time to explore these new options? How certain are you that the new addition will be a positive one and make the game more fun to play for longer? Would your time be better spent by simply adding more consumable content to the already working systems?

We’ll delve into ways of creating engaging mechanics and broadening your possibility space in later sections of the book; for now, let's look at other ways of limiting your content burn!