[Former Insomniac designer Mike Stout takes shares a useful rubric for judging the depth of play mechanics, including checks for redundant ones, in this in-depth design article, which contains examples from the Ratchet & Clank series.]
Often, in game development, a design that looks great on paper doesn't turn out as well in practice as you'd hoped. It comes across as "shallow" or "flat." Perhaps play-testers, publishers, or peers describe it as "needing more variety" or as "feeling repetitive."
Every game designer has heard these complaints at one time or another. I've bumped up against problems like this on every game I've ever worked on and there are three ways I like to approach solving them.
If the players felt the game overall didn't have enough variety you can add more game mechanics to the game. Think of this as increasing the game's "breadth."
If players feel that an individual game mechanic is flat and unrewarding you can refine that mechanic's "theatrics" by giving the player better feedback, more rewards, better effects, cooler sounds, more personality, a cooler camera, or other bells and whistles. After theatrics refinements, players will often -- with no changes to the underlying gameplay -- tell you the problem is fixed.
If players feel that an individual game mechanic "isn't giving them a good enough challenge," or feel that "the mechanic is fun at first but gets old quickly," you need to add depth to your mechanics.
While each of these could be the focus of its own article, this article will focus on perhaps the trickiest of the three: depth. By the time you're done reading this article, I hope to describe for you the tools I use to find out why a game mechanic doesn't feel deep enough. Even better, I hope to impart a few techniques that I've found help a lot when it comes time to fix a shallow game mechanic.
Before diving into a discussion on depth, I wanted to define a couple of terms that I'll be using a lot in this article:
Game Mechanic: When I say "game mechanic" I'm referring to any major chunk of gameplay in a video game. Using the classic The Legend of Zelda: A Link to the Past as an example, here are a batch of game mechanics: sword combat, block pushing, boomerang throwing, swimming, button-based puzzles, hazard-avoidance, use of specific weapons, etc...
Challenge: A challenge is any in-game scenario that tests the player's skill at a specific game mechanic. An example of this would be an individual room in a Zelda dungeon, a grindrail segment in Ratchet & Clank, or a combat encounter in Halo.
Dictionary.com defines depth as: "The amount of knowledge, intelligence, wisdom, insight, feeling... evident either in some product of the mind, as a learned paper, argument, work of art, etc." As is evident from the scope of this definition, depth can be an incredibly personal term, and can mean a lot of different things to a lot of different people.
To me, it describes a sweet spot -- that point during a game where the player can repeatedly display his mastery of a game mechanic. Challenges never stay the same long enough to be boring and yet they also don't change so fast that the player can't enjoy his mastery over the game.
Clearly this "depth" is something we want to achieve in many of our mechanics, but it's often less clear how to obtain it.
In my experience, in order for a game mechanic to be deep it needs two very important things:
When a player enters a challenge, he must have a good idea of what his objectives are. Another good way to put this is to say that he must be able to clearly visualize the completion state of the challenge.
In The Legend of Zelda: A Link to the Past, when players see a door that looks like this, they know they must find a special "Boss Key" to go through. These doors are a good, though simple, example of an objective. Once he sees the door, the player knows he needs to find the key and bring it back.
Clear objectives are a must if you want to create depth in your game mechanic. As I mentioned before, if the player doesn't know what the completion state of the challenge should be, he's reduced to floundering about and trying things randomly instead of demonstrating his mastery of the game's mechanics.