I applaud your attempt to map the literary concepts of Plot and Narrative (or Story, as you call it) onto game terms. I think I know what you're trying to do: there's a big difference between games where you are allowed to visit, say, planets or cities or places in any order (Story Non-Linearity) while still following a Linear Plot (since your decisions make no noticeable difference), and games where your decisions in even a linear sequence of Story Events can affect the Plot (since you can be forced to go to place A, then B, then C, while making dialogue decisions X, Y, and Z that diverge only at the end), thus invoking Non-Linearity of Plot. I hope you will excuse me for using your ideas as a launch point for my own take on your theories - the following consist of my attempt at clarifying what you briefly outlined:
Non-Linearity of Story, in this case, means Non-Linearity in the Narrative, in the observation of the Plot. The player, in this case, is the observer - and he may choose to freely dance about the Plot (by invoking Story Actions), going to and fro between different parts of the Plot (not to be confused with different *paths* of a non-linear plot) based on where/when he is and what he chooses to observe. He can even *do* different things at these different locations (again, Story Actions), whether it be fight monsters, buy items, or perform tasks and quests - but the fact remains that these actions do not change the overall Plot. They are, simply put, inconsequential: locally contained. This form of non-linearity can be clearly present without Non-Linearity of Plot, and it is in some sense the strategy followed by current MMORPGs, where each player's Story is different but the Plot of the world is always pre-defined (plausibility is feigned at through monsters respawning and instances resetting). But notice here that you *must* define Plot as the set of all non-player Events; it cannot be defined as player Events without being intertwined with the Non-Linear Story. In other words, if the Plot of the game *is* the player wandering around the world doing as he pleases, then really the Story and the Plot are one, because the player, through making his own Story, also then makes his own Plot. This little fact is important, because it's not always easy to distinguish between the two as it is in the case of RPGs with a predefined plot that the player can observe anyway he wants. Take Daggerfall, for example: which is the Story, and which is the Plot? And even if you *can* distinguish them, can you really make the argument, in the case of sandbox games, that Plot has any significance? The point of some RPGs is simply the Story, nothing more.
But of course, you can account for that by renaming Plot to World in these cases, and in fact that's probably the more encompassing term: for whereas underlying every novel there is always a Plot, underlying every game there is always a World.
Non-Linearity of Plot, however, is a more difficult concept to grasp. As you say, you're going to ignore randomness, by which I'm assuming you're limiting your discussion of Plot Non-Linearity to cases where players' decisions in the Story affect the Plot through Contact Points (thus, cases of plot non-linearity where King A dies if /random 0-1 turns out a 0 and lives if it turns out a 1 are ignored). A Non-Linear Plot, then, can be defined as a Plot where the existence and order of non-player-controlled Events are undetermined - until player decisions determine them. So far, so good. Now let's talk about Contact Points. IMO, while you describe as Story Contact Points and Plot Contact Points are really better served by Passive Contact Points and Decision Points. Why? Because you've already said that Contact Points are places where the Story and the Plot connect - which then makes it confusing to say that there's a Story Contact Point and a Plot Contact Point except to state the difference between two kinds of contact points: namely, one that is an imposition of the Story on the Plot, the other of which is an imposition of the Plot on the Story.
Now then, a Passive Contact Point is a point where a Plot Event imposes itself on the Story. Imagine a cutscene central to the Plot, but which you cannot effect in anyway, and which leads to some changes in the number of Story Events you have available to you (ie by opening up a new dialogue with a NPC, starting a new quest, allowing access to a new area, etc.) This cutscene would be a Passive Contact Point, because it changes the availability of Story Events but you have no control over the Plot through it. Note that this includes the vast majority of trigger events because while it's your Story Action that takes you to a trigger (ie you decide to go to the city Baldur's Gate), *nothing* changes fundamentally in the Plot - you're merely opening up new ways of observing. Hence the passive attribute. (OTOH, if you define Plot to be World, then the Passive Contact Point is moot because all Story Events are automatically Passive Contact Points with the World; but I won't go there).
A Decision Point, then, would be a point where a Story Event imposes itself on the Plot. This definition seems obvious - all it is is a point where your choice within the Story Event affects the next Event in the Plot (ie a dialogue tree where you can decide either to Save the Princess or Sell Her to the Evil Wizard, which then results in different Plot Events, one for each choice). Of course, in reality it's much more complicated, because here we're really abstracting away the layered hierarchy of plot structure. In essence, there is usually not *one* Plot (which MrBrown defines as the set of all non-player-controlled events, which is really too general as it assumes a singular ordering of Events, which is most definitely not true of many RPGs, which have multiple Plots running alongside each other, some of which have nothing to do with each other but are still Non-Linear in and of themselves).
Bringing it all together, we might ask ourselves: what are the possible combinations of Linearity with Non-Linearity in Plot and Story? What are their benefits and drawbacks, and how do they relate to our idea of Contact Points?
First, before we even attempt to answer that question, we must make something clear: linearity and non-linearity are one sliding scale on which the two concepts are the extremes. While there are definitely games that fall close to the extremities, very few games are absolutely linear or non-linear if we consider the set of all microscopic events. This is because ALL games are interactive, and the level of interactivity depends on how fine we reduce or abstact the events. A movie or book (except those choose-your-own-story novels), in some sense, are the quintessential Linear "games" while the ultimate Non-Linear game, as far as we can reach via human means, is the Imagination itself. Nevertheless, it maybe useful to think about what combinations of linear and non-linear plots / stories may mean.
1. Linear Story, Linear Plot
Most action RPGs and single-player FPS's fall within this category. The order in which you visit areas, which really constitutes your Story Events, are preordained. Even the items you use and the levels you are at are, in some sense, preordained and pre-balanced so as to ensure that you can defeat a boss by the time you get there. Here, you neither have the ability to change the Plot nor the ability to view the Plot differently through modifying the order or existence of your Story Events (except the microscopic decisions at the combatant's level).
The drawbacks are obvious, but there also benefits. For one thing, since Linearity is the attribute of cinema, having a Linear Story / Plot makes it alot easier for the game to be cinematic, since the developer can expect exactly where the player will go and how he will get there. Resources are thus efficiently applied with respect to player hours since the developers can spend their time ensuring that ALL the hours of the game are polished, since they're all important to the playthrough. It's also much easier to tell a story in the traditional sense through this combination, since novels are also Linear.
As a matter of fact, in the quintessential Linear Story, Linear Plot situation, there are no Decision Points because every Event is a Passive Contact Point which gives access to exactly one extra Story Event - the next one in the Plot. The Plot is therefore the Story and vice versa. What you see is what you get.
2. Linear Story, Non-Linear Plot
What is a linear story with a non-linear plot? A pick-your-own-adventure book. The order of Story Events are preordained: you must read the book from front to back, but you are allowed to make decisions that change what happens at particular points. Ah, you ask, but how is that different from a non-linear story? The answer is simple: because the availability of Decision Points do not change the fact that each Event is essentially a Passive Contact Point that gives access to exactly one extra Story Event - the next one in the Plot you've chosen. Therefore, while you choose what happens in the Plot, you do *not* choose whether to entertain those choices. You *must* choose, in other words, at certain junction points, and you *cannot* choose to skip that choice but continue to play.
Games like these are a-plenty (any game that leads you by the nose through a series of choices, really), though they usually have a bit of Story Non-Linearity in the beginning. Take, for example, the last stretches of KOTOR, after you've visited all the planets. Here, you clearly can choose between the Light Side and Dark Side endings. But can you choose to not make that choice? Can you choose to make that choice sooner than when you did by skipping one of the planets? No - because the Story Events at that point are limited. You *must* have gone through each planet before you are given that choice, and you cannot go back to a planet once you're past a certain point.
The benefits and drawbacks of this approach are as before: less work but less freedom, too. To be honest, though, I would say that this approach is far more preferrable than the next one for CRPGs, simply because plausibility can be maintained in a Linear Story with a Non-Linear Plot much more easily than can be maintained in a Non-Linear Story with a Linear Plot. For one thing, you can *see* yourself being forced into a series of actions that result in choices, and the best games justify that forcing through some device (ie in Half-Life 2 it's simple survival, in KOTOR it's a matter of urgency, in BG2 Irenicus has your soul, etc.)
3. Non-Linear Story, Linear Plot
What's much harder to believe in is the fact that you are simply incapable of making a difference whatever it is that you do. Non-Linear story with a Linear Plot simply means that you can go anywhere you want and do whatever it is that you want, but that whatever you do has no effect on the Plot itself. Of course, the *smart* designers limit your range of choices so that you can't do anything that will clearly change the plot (ie kill a key NPC, visit a plot development area before the plot gets there, etc.) But ultimately the idea is that you are given relative freedom as to observing the unfolding of the Plot from different perspectives (though sometimes even this is too hard and the developers just give you some small amount of time to wander around aimlessly before pigeonholing you into a Linear Story, Linear Plot situation ala ToB), but no ability to change the unfolding of said Plot.
In short, there are no Decision Points, though there maybe many Passive Contact Points (depending on how much the devs want to keep you on track with the Plot) and many Story Event choices. Go anywhere, see anything, but don't touch - or rather, touch, but don't break.
The drawbacks are, as stated, plausibility and freedom - these kinds of games have a tendency to fall into the category of Morrowind - games where the world isn't convincing enough for you to be engaged in the Story, largely due to the fact that your actions are mostly inconsequential with respect to an absent or neglected Plot. Of course, these games can also be done right, in which case the Story becomes the Plot and it doesn't matter, then, because you'd have achieved #4. Most MMORPGs clearly fall into this category also, and the trick is the same: making the player believe that his achievements in-game (his Story Events) are significant in and of themselves, regardless of the Plot that he has no effect on.
4. Non-Linear Story, Non-Linear Plot
Presumably the holy grail of non-linear games combine non-linearity of story with non-linearity of plot. Personally, I tend to think of this combination as economically infeasible because once you're able to attain both non-linearity of story and non-linearity of plot, more often than not you'll also be able to split the different paths of the plot into separate games and sell them that way for more $$$. At least, that's the theoretical extreme, the utopian non-linear RPG where you can go anywhere you want starting at level 1 and make an impact on the workings of the world wherever you go: the world simulator.
And really, this is what it's all about if you look down the path far enough: the world simulator is the ultimate non-linear RPG, the fully interactive sandbox where anything and everything is possible - yet in such lush detail, in such dramatic flourish, that the Plot, far from being absent as in #3, is present in every Event. In fact, there can't be one Plot in such a world - there must be many... Potentially infinite plots that intersect and intermix, generating a great tapestry of stories each of which are in and of themselves enough to be the Plot of a game or book or film. That is the final goal.
But on the way there, we need to be more realistic: what is a practical non-linear story combined with a non-linear plot? Well, we can't have infinite stories, so we have to limit the number of threads in the Plot. Then we have to ensure that you can approach these threads from a relatively open pool of Story Events - in other words, there should be many Contact Points, both Passive and Decision, and they shouldn't be *forced* into the game but actually make sense (ie, if I decided to visit the Dark Lord at level 1, my encounter with him in the Plot shouldn't be as if I was visiting him as the level 999 Uber Hero of Zork).
This is where, of course, many people get *really* upset about the exponential growth factor. With Non-Linear Plots, we merely had a branching factor of about 2-3, depending on number of decisions. Thus, if we kept the number of game-changing decisions down to 3-4, Non-Linear Plots are manageable. But consider a Non-Linear Plot in conjunction with a Non-Linear Story: you'd have to, in the worst case, multiply by a factorial factor (since order matters), which would get impossibly big very, very fast. Thus, this approach here really doesn't work if we want to be complete. Instead, as in trying to solve NP Hard problems in computer science, we'll need tricks.
And Fallout, really, is one such trick. Instead of making one humongous Plot that you can visit and change at various points, Fallout has *local* Plots that are *locally* changed (and presented to you locally at the end of the game). It then makes the *locals* available in a Non-Linear fashion, which constitutes its Non-Linear Story. Thus, the local Plots are kept simple - they branch once, or not at all, while the locals are kept largely independent, so that they don't affect each other on a combinatorial basis. What this translates to is a tree-like structure, instead of a web-like one, and that cuts down the resources required by an exponential amount.
This fact, however, presents to us a dilemma: Fallout was able to keep its complexity to a minimum through having Plots that were not long, continuous epics. But what if we wanted a continous plot, such as the one in the BG series? What if we wanted the novel-like stories of the FF series? Unfortunately, what you sacrifice for Non-Linearity will always be the complexity of the individual Plot. The more complicated a Plot is, the more involved the characters, the more important the order of events, the harder it is to make Non-Linear. And that's common sense - but now we have an inkling as to why it's common sense.
For this to make sense, I need to introduce one more distinction, namely that between the Passive Contact Point and the Plot Checkpoint. For you see, I kept mentioning Passive Contact Points that limit the pool of Story Events to exactly one when really, these can be organized into a separate category altogether. What the Plot Checkpoint is is an Event that furthers the Plot, that develops it in some way, but *without* contributing to the Non-Linearity of either Story or Plot. That is, such an Event does not add, cannot change, and can only remove possible Events from the pool of Story and Plot. There are a *ton* of these in modern RPGs of every kind. Every cutscene, every time a NPC speaks non-canned dialogue, every FMV - all Plot Checkpoints. These Plot Checkpoints combine together in a linear fashion, one after another, to create the complexity of a Plot: its nuances and subtleties and dramas. They are the essence of what makes a Plot complicated and involved. But they're undeniably linear and interdependent on the order of operations, because you largely can't have Plot-development cutscenes or dialogue or FMV without knowing what to expect already. Thus, if we were to make each of these Plot Checkpoints either a Decision Point or even a Passive Contact Point that allows for multitudes of different actions, we would instantly be faced with an exponential explosion of choices.
Thus ends this contemplation: non-linearity is a great concept, but its application comes with great sacrifices to the level of involvement and detail you can give to a particular Plot.
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