Game design theory essay...
I did a lot of thinking about level design over the weekend. For most of it, I stuck to shmup levels - my thoughts centered around Machine City - but I kept coming back to level design "in general", which to me means applying the same principals to a variety of genres.
That's the problem with being a theorist. You always want to generalize.
Anyhow, one of the things that I wanted to clarify is play types. I'll also clarify player vision some more at some point, in another essay.
Most games play either fast or slow. Most of the time, a fast game will eat levels for breakfast, pound through acres of map. Most of the time, a slow game will use the same map and criss-cross over it a half-dozen times. There are exceptions, and this simplified level design philosophy is really only true of one-player and co-op games.
Either way, one of the things you need to do is to keep the player from getting bored of the pattern of gameplay. Some games do this well, some games bore the player to tears. This is more than just offering them play they don't much like: it's offering them too much of a given kind of play.
An example of each can be found in the game No One Lives Forever 2. If you haven't played this game, go buy it. It is my second favorite first-person game, period, and I haven't seen any game which matches it for flawless quality on every level. Save level design, which was occasionally quite good and occasionally quite bad.
Much of this game is slow play. You're playing a spy, after all. A good example of slow play being used well is the undersea base. You play through the whole base. It gives a sense of large size and scale, despite the fact that it is a rather small level. It goes on a little long, actually, but not too badly thanks to the ever-increasing variety of encounters.
Then, after a boss fight, you get to revisit the station, seeing it from a radically different viewpoint trying to escape it as it floods.
This is something similar to what Doom III tried to do: show you the base "before" and "after". "After" is inherently more interesting for various reasons, so it is natural to try to stretch it out a bit. The undersea base doesn't, but I wouldn't have minded a bit more level on the escape.
Anyhow, on the other side of the spectrum is India, the city. A large, open level in which you can't kill anyone. All you do is run back and forth on errands, dodging cops. On the third playthrough, you can blitz all the India city levels, but it's a protracted and rather painful experience the first time through.
Later on, you revisit India city. To do what? Run errands and not kill anyone. Wow, and this time the errands are even more inane, featuring running back and forth for water while being shot at. Across the same paths. Over and over. To save people who are too stupid to climb through the giant, open window two feet from them. There are a few moments in which HARM's doomed Indian soldiers attack you, but these are bizarre episodes which aren't really explained: why are they attacking you instead of trying to escape their demise? Although a nice attempt to keep the level from being "turn off the computer" bad, they break suspension.
On the surface, these two levels appear very similar. You run through a lot of corridors in each, can approach them both by stealth, have an intermission (boss fight in one, several levels in another), then work through the "ruined" version.
But a play type analysis shows a very different set of levels. Both levels initially play "slowly", although one is a "conquest"-style play and the other is a "foxhunt"-style play. One is voluntary slow play, the other is involuntary. As you go through the undersea base, you choose to go slowly, killing the threats and making that part of the base safe for you. In India, you are forced to go slow because you need to time your movements to keep you alive. I believe this kind of "foxhunt" play to be distinctly inferior, since it is nonadaptive and submits the player to the same challenges repeatedly.
On the last visit to these levels, things are distinctly different. The undersea base speeds up to a moderately fast game where India slows down even further. India remains "foxhunt" play, but the undersea base becomes "shockwave" play: you blast through each part of the level and leave nothing you ever bother to revisit.
My dislike of "hunted" play aside, using the same gameplay every time you hit a level, you might as well be playing the same level. Shake it up!
As a basic rule, the human brain only stays interested in something for about 20 minutes. Some people can go for vastly longer, but few go for shorter. This means that you need to change modes of play ("patterns") no less often than once every twenty minutes. You don't have to change it for long, but you need to change it. And in order to get maximum use out of a level design, you can get an entirely new experience out of a map by hitting it with a different style of play.
"Twenty minutes?" you say, "that's a long time to be sneaking around without a gunfight. It seems to me that most games interrupt with a new style of play every two minutes!" Yes, for two reasons:
1) Resetting the clock insures maximum attention.
2) Many players have an exceedingly slow first play-through. You can beat XIII in 130 minutes? Sure, but the first time it took you thirteen hours.
So level designers do - and should - err on the side of short attention spans.
To give you an idea of some of the basic kinds of play, here is an incomplete list. Feel free to suggest things I've missed:
Foxhunt: moderate to slow play speed
Explanation: Level is littered with invulnerable threats that have few successful approach vectors; player speed is therefore slowed to allow for higher relative vision.
In English: Effectively a puzzle level, foxhunt emphasizes careful watching and considered movements on pain of death. The slower the play style, the more careful you have to be not to exceed your 20-minute maximum play length.
Conquest: slow play speed
Explanation: Player earns ownership of level.
In English: The player destroys enemy presence in a level so that he owns it. Although this is, in itself, probably medium-speed play, the ownership of the level then encourages the player to carefully search every room. Depending on the player's level-affecting capabilities, they may slow the game even further by destroying parts of the level or by building new structures.
As with foxhunt, care must be used to insure that a player doesn't go more than 20 minutes without a play style change.
Hunted: fast play speed
Explanation: Player vision limits are enforced by forcing player movement. Play speed is therefore accelerated.
In English: Effectively a timed level. Rising water, a rampaging demon, and other active forces push the player to keep moving or lose the game. This play style can also result from moving levels. For example, conveyor belts.
Please note, "hunted" and "hunter" levels are functionally the same. Whether the player is forced to move along by a wall of fire or whether he has to constantly chase a monkey, the core idea is that there is a time-sensitive thing pushing the player to constantly move forward.
Shockwave: moderate to fast play speed
Explanation: Player's only goal is to get through the level
In English: This can be very similar to conquest, but the design is such that there is no way to slow down and appreciate your hard-earned territory. Perhaps there is a constant stream of soldiers, or perhaps there is simply nothing worth appreciating.
Often, "shockwave" is almost indistinguishable from "hunted". The difference is that when you are hunted, something is actively pushing you. Shockwave may send streams of soldiers, but your skill could be enough to hold them off forever. Shockwave may slam doors shut, but only after you use them - not as a possible loss condition.
These four types arise from basic elements of play, which I imagine I'll cover sometime. I don't think it's a full list, but each of those has a very different approach, both for play and design.