Games by definition require some kind of interaction from the player. Obviously the level of interaction differs from game to game, but have you ever noticed that the higher-quality games often allow the player to approach a situation from various angles and interact with the problem in different ways? We can simplify this… the “variation in a game’s methods for the player to solve its problems” can be therefore defined as the game’s depth.
A game with very little depth is one that will often be a one-time experience, such as a game entirely made of quicktime events; you can’t solve the problem in any other way except hitting the specific button requested. To further this example, a game with high amounts of depth will allow many different possibilities, such as a game like DOTA where the hundreds of characters, hundreds of items, playstyle differences, and specific timing of actions make each match of the game unique in every circumstance, and therefore making it a game that can be played for literally tens of thousands of hours without boredom.
So after knowing all of that, how should a developer take this into consideration? A game developer with little amounts of experience will likely make a game with little amounts of depth; the game might be “good” by most people’s standards, but there will be extremely little replayability due to the uniform way of solving a problem. It takes an experienced developer to offer the player copious amounts of choice, and then balance those choices out so that players aren’t compelled to pick one choice over another, and then making sure that these choices cater to every player by covering a broad spectrum of playstyles.
As an example, think of a projectile in an action game. The projectile is coming towards you, so how do you deal with it? A game with inherently good game design would allow the player many ways to deal with this problem, such as moving out of the way, strategically allowing the shot to hit you to give you a future positioning advantage, destroying the projectile with a weapon, blocking it with a shield, etc. A defensive-natured player would likely prevent the projectile from hitting them, whereas a more offensively-minded player might risk their health in order to give them an advantage in the fire-fight. Almost all players fall between these two styles, and the choices cater to both skill and playstyle, giving every player an option that they prefer, and others that also could be attempted for variation’s sake.
Important Takeaways: A game without depth won’t last long in the minds of most players. Most popular and critically acclaimed games today have an exceedingly high amount of depth of gameplay, allowing the player to continue playing without worrying about the inability to solve situations as they see fit, and making sure that they do not become stale. Inexperienced developers might forget to think about their game’s appeal after the new player experience, and this is how you make a game that will be forgotten in time. Even games with relatively simple concepts like Rocket League or arena shooters such as Quake give the player the ability to do things as they please, so they maintain their depth. The depth of your core gameplay loop is paramount to player enjoyment — don’t let your potential fans down.