Posted On: 2020-04-13
Keys are something of an essential part of game design. In nearly every game, content is gated in some way, and keys are the means of accessing what lies beyond each gate. Whether it's getting a literal key to open the castle gate or a figurative key (ie. a magical artifact) to unlock access to the big-bad, keys control the player's access to the various parts of the game.
For all the different kinds of keys in a game, perhaps the most fascinating (to me) is the mechanic-as-key. Long a staple of action-adventure games, the mechanic-as-key is any time a game's systems are used as a gate, and some in-game mechanic can be used by the player to overcome (unlock) that gate. Such a mechanic may be something that is only used rarely (such as a hammer to drive pegs into the ground) or a core part of the character's move-set (such as an extra-high jump). Additionally such mechanics may be unlocked explicitly (such as finding a new tool) or be always available, and merely unlocked by making the player aware of it*.
Player skill can also be used as a key. When gating access in this way, the player must demonstrate some particular skill in order to experience certain content. The most obvious example of this is game difficulty: in many action games, difficulty increases as the player progresses, requiring the player to demonstrate greater skill to reach the next challenge. In theory, the player should be able to handle the increased difficulty, since prior experience with the game should improve the player's skills (such as the timing and reflexes to use the core mechanics optimally.) In practice, every player is different, so a manageable difficulty for one player might be insurmountable for another. Thus, one player might be able to access all the content in the game, whereas another might be blocked off from some of it*.
Beyond difficulty, there are many other player skills that can be used as a key. Observation is a particularly popular one for gating optional "secrets": for example, many games have subtle clues when a wall is "fake" (the player can pass through it). An observant player might notice such clues, while a less observant one might pass right by without a thought. Additionally, many games use the player's mental skills (such as planning ahead, thinking laterally, or deductive logic) as their skill "gate". For puzzle or strategy games, this is often closely connected to difficulty (since the game is training the player to use those skills), but they can be used even in genres that don't normally emphasize mental skills. For example, an action game might have a one-off puzzle involving the player using their weapon to detonate an unreachable explosive that opens access to a new area.
Going back to mechanic-as-key, one of the quirks about it that makes it particularly fascinating to me is that a player's ability to access it is often gated not just by the mechanic but also by their underlying skills with the mechanic. Whether that's physical skills (such as reflex/timing for a tricky jump) or mental skills (such as reasoning about how the mechanic will influence other game elements), an individual player's ability to "unlock" a gate is not just limited by their access to the "key", but also by their ability to use it correctly*.
Consider a game with a particularly difficult jump: a narrow pass through walls covered in spikes requires that the player character follow a precise jump trajectory in order to get through safely. At the end of the jump, they must then use a mid-air dash to land in the only safe place available. Players who do not yet have the mid-air dash mechanic will find the jump is impossible, and therefore they cannot pass. Players who do have the mid-air dash technically can pass, but many of them* will lack the necessary player skills to execute the jump with the necessary precision.
One of the designer's biggest responsibilities is to help the player to develop the necessary skills to succeed. When mechanics are introduced, players are often taught how to use them*, and skills with them are routinely tested, both to provide adequate practice as well as verify that the player can still use those skills on demand. When gating player progress with a novel application of an existing mechanic, the designer often designs relevant affordances into the mechanic, to make the new application feel less arbitrary and more natural**. Thus, while the player may feel a sense of triumph as a result of correctly applying the mechanic, much of the groundwork that made it possible was at the hands of the designer.
As I work on the design for the mechanics-as-key elements in my current project, I feel the weight of the designer's responsibility. With each novel application I envision, I step back and ask myself: "how can I help the player to make the logical leap necessary to understand this?" What's more, whenever I consider a particular approach, I also have to wonder whether it is too "hand-holdy": any sense of accomplishment is often quite strong if the player feels ownership over the solution, but if they feel like they were told what to do, that feeling is often diluted. It is a careful balancing act between being too helpful or too demanding. Fortunately, thanks to resources like playtesting and feedback, I don't have to get it right on the first try.