Puzzle Logic

[Warning: I'm going to dissect the GUE Tech locker puzzle from Zork Grand Inquisitor. I expect the statue of limitations on it have run out, but nevertheless, you have been warned.]

At some level, puzzles in adventure games are supposed to be a challenge. Overcoming or finding a way past obstacles is part of the enjoyment of many games. However, puzzles can become too much of a challenge when we can't figure out how to solve them. Sometimes we miss a clue or don't take the time to really think things through, but other times it seems as if there is no way to solve a puzzle short of reading the designer's mind.

I believe that the logic of a puzzle plays a large role in making it solveable or insurmountable. The thing is, the logic of puzzles doesn't necessarily need to be the logic of the real world.

I admit this sounds like a bad clue from The Riddler: when is logic not logical? Let me explain by breaking puzzles down into three broad categories: "common" sense, self-consistent, and wacked.

"Common" Sense

"Common" sense puzzles are ones which require you to apply a bit of real-world knowledge to solve it. Perhaps you have to know a little bit of trivia, or apply a common object in an unusual manner.

I see I am spouting vagueness. Let me give you a contrived example. You're locked in an office, but you know that the exit will automatically unlock if only you can set off the fire alarm. There's not a lot in the room: a desk, maybe a desk lamp, a chair, and the fire sensor above the desk.

You riffle through the desk, only to find no papers or handy oily rags with which to start a fire. You don't even happen to have a matchbook on you, since you're trying to quit smoking. Besides, a real fire could easily get out of control and kill you. What can you do?

You can remember that that desk lamp, if it's an incandescent bulb, gives off heat. Get on top of the desk, turn on the lamp, and hold the bulb near the sensor until the fire alarm is tripped.

Granted, I'd need to give you some clues to make this puzzle fair, like telling you how hot the lamp gets when you turn it on. However, it illustrates my basic point: you have to remember that incandescent bulbs not only give off light but also heat. You have to apply some real-world knowledge and logic to the situation.

In one sense, these kinds of puzzles are the easiest to design. You don't have to spend too much time figuring out the logic of the situation, because the real world hands most of that to you. All you have to do is figure out what the unusual situation or needed object will be. In another sense, these puzzles are hard to design because they can be hard to make fair. That's why I put the quotation marks around "common." What you or I may consider to be common knowledge may not be. Does everyone know how to cook a baked potato, or how many feet are in a kilometer?

Self-Consistent

While many puzzles fall under the previous category, there are those which have a logic all their own. Consider the machines in Myst, or most any machine-studded adventure. You have to twiddle with them, figure out how they work, and then apply that knowledge.

To be reasonable, these puzzles need to be self-consistent. They have to follow a deducible set of rules which can consistently be applied. The logic they follow may have nothing to do with the real world, but there is a logic nonetheless.

One of my favorite examples of this kind of puzzle is the GUE Tech locker puzzle in Zork Grand Inquisitor. In the abandoned magic college of GUE Tech, there are a group of lockers that you want access to. However, they're locked in some non-obvious way. How do you open them?

If you look around the lobby of GUE Tech, you'll find a bulletin board. On it is a note which reads something along the lines of, "The vending machine has broken; lockers will be unavailable until it is fixed." Hm. Then, if you look at the lockers and at the items in the vending machine, you'll notice that they are both arranged similarly.

It turns out that, if you put money in the vending machine and press a button, the corresponding locker opens. In fact, one of the items will get stuck in the machine, and the corresponding locker will also be jammed.

Stupid? Yeah, probably. Goofy? Undoubtedly. But it follows its own logic, one which you can discover by noticing the clues and by experimenting.

The trouble with these kinds of puzzles is that players must be able to work out the logic behind the puzzles. If the logic to a puzzle is too obscure and is not hinted at by clues, players will be unable to solve it except by thrashing about.

Wacked

Finally, there are the puzzles that seem to make no sense. They are the common-sense puzzles which require non-common and hard-to-find knowledge; they are the self-consistent puzzles that are not consistent or have logic that can't be deduced. Maybe they require you to read the designer's mind to know what's going on. Perhaps they are examples of the dreaded guess-the-verb/hunt-the-hotspot puzzles.

Whatever the cause, these puzzles cause unplanned anguish and decrease our enjoyment. They are the puzzles which make us want to stop playing adventure games.

How, then, do you make puzzles fair? I'm glad you asked.