# Door Key Level Pattern

Problem: We want to give the player the illusion of freedom and nonlinearity, without letting them 'skip' subquests or level areas we've created, and without letting them experience the game in the wrong order.

Solution: The level has branches; one branch leads to a door - the other branch leads to a dead-end and a key. The player has a choice at this moment. If he goes down the branch towards the door, he'll realize he needs a key to open it, and backtrack and try the other branch. This branching can be expanded ad infinitum, and you can introduce doors for which the key will become available much later, rewarding memory.

Possibilities:

• 1 key opens 1 door
• 1 key opens many doors (Metal Gear Solid)
• Many keys can open 1 door (Deus Ex)
• Many keys needed to open 1 door (Spider-Man: The Movie)
• Keys open all doors, but just once (Zelda)
• Grants flexibility, decision making, in choosing order of opening doors.

Thoughts: Some people tire of keys and doors, but find it more interesting than straight linear levels. It provides the opportunity to explore in your own way. Too much, however, and people can tire of seeing the same landscapes over and over again, and the game can become a chore.

• MeaningfulChoices (the destination of conversation about whether Meaningful``Choices are important or not.)

Although I think the Key/Door pattern is one worth mentioning, I don't think it's always (or even often) for the reasons stated. I think locked doors often serve instead to add a ClearShortTermGoal. In many games, players normally have an implicit goal of progressing forward. A locked door prevents the player from doing that, and so the player acquires a new, extra, explicit goal of finding a key to open the locked door and thus return to their overarching goal of progressing forward. Progressing forward as a goal has no particular structure or pacing, as it generally happens as a constant. Facing a locked door, on the other hand, has a very specific structure - the player discretely transitions from progressing unhindered to being actively impeded, which adds an element of tension. The player then goes searching for the key. All this time (assuming the game world is interesting) there is hopefully some degree of curiousity or anxiety or anticipation in the player about what is behind the locked door (which can be furthered greatly if the game designer adds sound cues near the locked door to make the other side of it seem fascinating or horrible or whatever)... or, well, that's a possibility anyway. The Playstation 2 Castlevania has a fantastic example of this sort of thing in the very first area. At any rate, the player searches for the key, the key is found, and the player returns to the locked door. Again, there is, hopefully, more tension and anticipation in the player as this happens. Finally, the player reaches the locked door, passes it, and there is release. The main problem with Key/Door situations in many games, to my way of thinking anyway, is that they're just thrown in poorly and overused so often.

Key/Door is also a very fundamental component of an element that shows up constantly in many of Nintendo's best games. In Metroid Prime, for example, as you play through the early part of the game, you frequently see ledges that you can't possible reach. Eventually you earn a double jump ability, and at that moment, you have access to all of the previous areas that were unreachable. In practical terms, this has an indentical structure to Key/Door, with the ledges functioning as locked doors and the double jump functioning as a key, but there is a slight logical leap or puzzle solving element embedded as well. All of the Zelda games with their items and all of the recent Castlevania games exhibit similar structures.

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